Bob and Sue are working on an test review. Bob could complete the review in 6 hours if he was working by himself. Sue could complete the review in 12 hours if she was working by herself. Which of the following equations is set up correctly to determine how long it would take Bob and Sue to complete the review while working together?

the solution is 12x-6y

c.   x=2.4cm

step-by-step explanation:

similar triangles are triangles which have the same shape but not the same size. this means their angle measures are equal but their side lengths are not instead they are proportional. to solve, we will set up a proportion and solve.

a proportion is two equal ratios set equal to each other. we form the ratios by finding corresponding sides (sides which match to each other on both triangles by their position). out ratios will be one side of the small triangle over the corresponding side on the big triangle as shown below:

.

to solve the proportion, we'll cross multiply by multiplying numerator with denominator across the equal sign.

you can't solve x because it is 2 linear equation and you only have one equation