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Lesechka [4]
2 years ago
3

Alex was counting his coins by 2s. because one coin was left over he counted them by 3s. again there was one coin left over so h

e counted by 4s the 5s the 6s and finally 7s. each time there was one left over. knowing that alex did not have more than 800 coins exactly how many coins did he have
Mathematics
1 answer:
lesya [120]2 years ago
5 0
 (My process of thinking)
 
 Well, we know that however many coins he does have, x, is not more than 800 AND cannot be divided by 2, 3, 4, 5, 6, or 7. So, I need to find a number that can divide into 800 but the rest cannot.
x mod 3=1, x mod 4= 1, x mod 5 = 1 and x mod 7 =1. 
Note that if x mod 3 =1 and x mod 4 =1 then x must be of the form 12a+1. So (12a+1) mod 2= 1 
and (12a+1) mod 6 =1. That is you need not have the equations for 2 and 6. 
<span>To satisfy the 4 equations above x must be of the form (3*4*5*7)b+1 =420b+1. Knowing that x <800 we get that b=1 and so x=421. Alex had 421 coins!</span>
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What is the total surface area of the square pyramid below? <br><br>question above <br>​
Wewaii [24]

Answer:

132 m².

Step-by-step explanation:

What's the surface area of each lateral face of this pyramid?

Each lateral face of this pyramid is a triangle, with

  • a height of 8 meters
  • on a base 6 meters.

The base of this pyramid is a square. As a result, all four lateral sides are congruent. The area of each of these triangle is thus

\displaystyle \frac{1}{2}\times \text{Base}\times \text{Height} = \rm \frac{1}{2} \times 6 \times 8 = 24\; m^{2}.

The base of this pyramid is a square. The length of a side of this square is 6 meters. The area of the base will be

\text{Side}^{2} = \rm 6^{2} = 36\; m^{2}.

Put the five faces together to get the total surface area of this square pyramid:

\rm 4\times 24 + 36 = 132\; m^{2}.

8 0
2 years ago
Alex, Toby and Samuel are playing a game together.
Shalnov [3]

Answer:

1/9

Step-by-step explanation:

There are three places and three people.

Times them together for the total outcomes:

1/3 x 1/3= 1/9

8 0
2 years ago
a jogger runs 218 meters eastward then 72 meters westard then 62 meters eastward and finally 184 meters westward. For this motio
iris [78.8K]

Answer:

<u>Total distance = 536 m</u>

<u>Total displacement = 24 m</u>

Step-by-step explanation:

<u>Distance and Displacement</u>

A moving object constantly travels for some distance at defined periods of time. The total moved distance is the sum of each individual distance the object traveled. It can be written as:

dtotal=d1+d2+d3+...+dn

This sum is obtained independently of the direction the object moves.

The displacement only takes into consideration the initial and final points of the path defined by the object in its moving. The displacement, unlike distance, is a vectorial magnitude and can be even zero if the object starts and ends the movement at the same point.

For the question at hand, it's not known if the requirement is about the distance or the displacement, so we will compute both.

To compute the distance, we just add all the distances:

dtotal= 218 m + 72 m + 62 m + 184 m = 536 m

To compute the displacement, we must establish a positive direction as desired. Let's choose the east as the positive direction. Any movement eastward is considered positive and any movement westward is negative. We mentioned the displacement is a vector, but since we only have movement in the x-axis, we can only manage the signs. Thus, the total displacement is:

xtotal = 218 m - 72 m + 62 m -- 184 m = 24 m

Since the result is positive, the jogger stopped 24 meters eastward form the original point.

4 0
2 years ago
A contractor leans a 21-foot ladder against a building. The distance from the ground to the top of the ladder is 9 feet more tha
melomori [17]

Answer:

The distance from the ground to the top of the ladder = 18.7 feet

Step-by-step explanation:

The distance from the ground to the top of the ladder is 9 feet more than the distance from the building to the base of the ladder.

distance from the building to the base of the ladder.= X

The distance from the ground to the top of the ladder = 9+x

Solving the triangle using Pythagorean theorem

X² +(x+9)²= 21²

X² + x² + 18x +81= 441

2x² +18x -360 = 0

X² +9x -180 = 0

X= (-9-28.3)/2 or (-9+28.3)/2

Definitely x is going to be a positive number

So

X= (-9+28.3)/2

X=9.65 feet

The distance from the ground to the top of the ladder = 9+x

The distance from the ground to the top of the ladder = 9+9.65

The distance from the ground to the top of the ladder = 18.65

The distance from the ground to the top of the ladder = 18.7 feet

6 0
2 years ago
Tia’s tent is in the form of a triangular prism as shown below if Tia plans to waterproof the tent excluding the pace what is th
Marat540 [252]

just multiple it all together

7 0
2 years ago
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