Answer:
a) 375
b) 7062.75 mm²
Step-by-step explanation:
b) We need to find the shortest possible width and length to get the smallest possible area.
To get the boundaries for 19.4, we go on to the next significant figure (the hundredths) and ± 5 of them.
The boundaries are, therefore: 19.35 - 19.45
As for the length, we can see they've added 5 units as the measurement is correct to 2 sig' figures, which is the tens.
And so, if we do as we did before, we go to the next sig' figure (the units) and ± 5 of them, we get the boundaries to be 365 - 375.
Now, we just multiply the lower bounds of the length and width to get the minimal/lower-bound area:
365 * 19.35 = 7062.75 mm²
Let the distance of the first part of the race be x, and that of the second part, 15 - x, then
x/8 + (15 - x)/20 = 1.125
5x + 2(15 - x) = 40 x 1.125
5x + 30 - 2x = 45
3x = 45 - 30 = 15
x = 15/3 = 5
Therefore, the distance of the first part of the race is 5 miles and the time is 5/8 = 0.625 hours or 37.5 minutes
The distance of the second part of the race is 15 - 5 = 10 miles and the time is 1.125 - 0.625 = 0.5 hours or 30 minutes.
It has not been indicated whether the figure in the questions is a triangle or a quadrilateral. Irrespective of the shape, this can be solved. The two possible shapes and angles have been indicated in the attached image.
Now, from the information given we can infer that there is a line BD that cuts angle ABC in two parts: angle ABD and angle DBC
⇒ Angle ABC = Angle ABD + Angle DBC
Also, we know that angle ABC is 1 degree less than 3 times the angle ABD, and that angle DBC is 47 degree
Let angle ABD be x
⇒ Angle ABC = 3x-1
Also, Angle ABC = Angle ABD + Angle DBC
Substituting the values in the above equations
⇒ 3x-1 = x+47
⇒ 2x = 48
⇒ x = 24
So angle ABD = 24 degree, and angle ABC = 3(24)-1 = 71-1 = 71 degree
There would be 12 litres in the tub after 4 minutes