Dory biked 143 miles last month.
Let x be the number of miles Karly biked
Dory biked 11 times as many miles as Karly, therefor, Dory = 11x
The total number of miles back by both is 156
The equation will be:
11x + x = 156
Before we can get the number of miles Dory biked, we must first get the number of miles
Karly biked represented by x.
Get the x
12x = 156
12x/12 = 156/12
x = 13
Karly = x = 13 miles biked
Dory = 11x = 11(13) = 143 miles biked
To check:
11x + x = 156
11(13) + 13 = 156
143 + 13 = 156
156 = 156