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2 years ago

A girl had 20 coins in nickels and dimes whose sum was $1.40. She spent 65cents , using 8 coins. She now has ? nickels.

Mathematics

2 answers:

abruzzese [7]2 years ago

6 0

Answer:

$0.75 nickels

Step-by-step explanation:

$1.40-$0.65=$0.75

$0.75 nickels

Marina CMI [18]2 years ago

3 0

Answer:

9 Nickles

Step-by-step explanation:

Let n = number of nickles and d = number of dimes

d + n = 20 -----------(1) [ total number of coins 20 ]

Dimes = $0.10

Nickles = $0.05

0.1d + 0.05n = $1.40 ---------- (2) [20 coins worth $1.40]

Since d + n = 20

∴ n = 20 - d

Let's substitute n in equation (2)

0.1d + 0.05(20-d) = 1.40

0.1d + 1 - 0.05d = 1.40

0.1d + 0.05d = 1.40 - 1

0.05d = 0.4

d = $\frac{0.4}{0.05}$

d = 8

Now put value of d in equation (1)

n + 8 = 20

n = 20 - 8

n = 12

Let's check 8(0.1) + 12(0.05) = $1.40

Now she spent 65 cents using 8 coins.

The only combination of 8 coins worth $0.65 is

5d + 3n = $0.65

Hence, she used 5 dimes and 3 nickles.

Now she has 12 - 3 = 9 Nickles

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Answer:

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Step-by-step explanation:

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2 years ago

A farmer plants corn in 1/4 of his field. He plants white corn in 3/5 of the corn

bija089 [108]

Answer:

$\frac{3}{20}$

Step-by-step explanation:

Fraction of the total that is for corn (TC - Total corn):

$TC=\frac{1}{4}$

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$WC=\frac{3}{5}$

we need to find the fraction of the whole field that is for the white corn.

For this we need to find how much is $\frac{3}{5}$ out of the $\frac{1}{4}$ destinated to corn, and this will be the fraction of the total that is for white corn. We find this fraction by multiplying the fraction of corn ( $\frac{1}{4}$ ) by the fraction of white corn in the corn section ( $\frac{3}{5}$ ).

I will call the total fraction of white corn TWC, thus:

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the answer is: $\frac{3}{20}$ of the whole field is planted with white corn

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2 years ago

Amir drove from Jerusalem down to the lowest place on Earth, the Dead Sea, descending at a rate of 12 meters per minute. He was

SSSSS [86.1K]

<h2>Answer:</h2>

First of all let's write the slope-intercept form of the equation of a line, which is:

$y=mx+b \\ \\ Where: \\ \\ m: \ slope \\ \\ b: \ y-intercept$

So we just need to find $m \ and \ b$ to solve this problem.

Moreover, this problem tells us that Amir drove from Jerusalem down to the lowest place on Earth, the Dead Sea, descending at a rate of 12 meters per minute. So this rate is the slope of the line, that is:

$m=-12$

Negative slope because Amir is descending. So:

$y=-12x+b$

To find $b$ , we need to use the information that tells us that he was at sea level after 30 minutes of driving, so this can be written as the point $(30,0)$ . Therefore, substituting this point into our equation: