Bethany can mow her family’s lawn in 4 hours. her brother colin can mow the lawn in 3 hours. which equation can be used to find x, the amount of time it would take for bethany and colin to mow the lawn together? .

In 4 hours Bethany did the whole fraction 1 of the house.

In 1 hour he would do 1/4 of it.

In 3 hours Colin did the whole fraction 1 of the house.

In 1 hour he would do 1/3 of it.

In 1 hour they would both do (1/4 + 1/3)

If it takes both of them x hours to finish 1 whole fraction of the house.

In 1 hour they will both do   1/x

That means that:

1/x = 1/4 + 1/3

That is the equation.   x can be solved for.