Question

Kenyon ran for 8 miles each week while training. Here is his record of the number of miles he ran.

Answer 1

Step-by-step explanation:

Let x be the miles Kenyon ran on tuesday

Let y be the miles Kenyon ran on thursday

Given,

Mon + Tues + Wed + Thu = 8mi

$1.2 + x + 1.6 + y = 8 \\ 2.8 + x + y = 8 \\ x + y = 8 - 2.8 \\ x + y = 5.2$

also given,

$y = x + 0.4 \\ - x + y = 0.4$

Now we have x + y = 5.2 as equation 1 and -x + y = 0.4 as equation 2

Using equation 1,

$x + y = 5.2 \\ x = 5.2 - y$

Substitute this equation into equation 2.

$- (5.2 - y) + y = 0.4 \\ - 5.2 + y + y = 0.4 \\ - 5.2 + 2y = 0.4 \\ 2y = 0.4 + 5.2 \\ 2y = 5.6 \\ y = 5.6 \div 2 \\ = 2.8mi$

Substitute y = 2.8 into equation 1.

$x + 2.8 = 5.2 \\ x = 5.2 - 2.8 \\ = 2.4mi$

Therefore Kenyon ran 2.4 miles on tuesday, and ran 2.8 miles on thursday.