Question

In the last race , the first car in the pit used 1 3/4 tanks of gas, the second car used 2 1/8 and the third car used 1 1/2 tanks of gas. what was the total positive or negitive change in the amount of gas for all three cars

Answer 1

Answer: $-5\frac{3}{8}$ tanks of gas

Step-by-step explanation:

Let the x be the number of tanks of gas, then

The amount of gas used by first car= $1\frac{3}{4}x=\frac{7}{4}x$

The amount of gas used by second car= $2\frac{1}{8}x=\frac{17}{8}x$

The amount of gas used by third car= $1\frac{1}{2}x=\frac{3}{2}x$

Thus, the total change in the amount of gas for all three cars=$\frac{7}{4}x+\frac{17}{8}x+\frac{3}{2}x$

$=x(\frac{7}{4}+\frac{17}{8}+\frac{3}{2})\\\\=x(\frac{14+17+12}{8})\\\\=x(\frac{43}{8})\\=5\frac{3}{8}x$

Since, the amount of gas $5\frac{3}{8}$ tanks of gas is used for all three cars.

Therefore, the total amount would be negative .

hence, the answer is  $-5\frac{3}{8}$ tanks of gas.