Question

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

Kenyon ran 0.4 miles more on Thursday than on Tuesday. Find the number of miles he ran on Tuesday and Thursday.
Monday= 1.2 mi. Wednesday = 1.6 mi
Tuesday: mi

Thursday: mi

Answer 1

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 / 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.