<span>D-21.4=87.9 \ solve for D
add 21.4 to both sides
</span><span>D - 21.4 +21.4 =87.9 + 21.4
simplify
D = 109.3</span>
The statement of the question tells us that 45% of the customers getting an oil change will have their car tires rotated. Therefore:
probability of both = 0.7 x 0.45
= 0.315
= 31.5%
50.........................
3/5 * X = 15
3/5 ÷3/5 * X = 15 ÷ 3/5
X = 25
The total length is 25 miles