a truck driver drove 1190 miles in 20 hours over two days

Question

a truck driver drove 1190 miles in 20 hours over two days. On the first day, her average speed was 65 miles per hour on the second day her average speed was 55 miles per hour. How far for how long did she drive on each of those two days?

Answer 1

Let x = hrs driven 1st day and y = hrs driven 2nd day.

Translate the problem into math (equations)

x + y = 20

65x + 55y = 1190

 

Divide the 2nd equation by 5: 13x + 11y = 238

Multiply the 1st equation by 11: 11x + 11y = 220

 

Subtract

2x = 18 => x = 9 (and  585 miles)

y = 20 - x = 11 (and 605 miles)