Question

If you can do 45 sit-ups in 3 minutes, than how much minutes does it takes to do 90 sit-ups??

Answer 1

We will solve this question using the ratio method.

∵ You can do 45 sit-ups in 3 minutes

∵ The number of sit-ups is 90

→ By using the ratio method

→ Time: sit-ups

→ 3 : 45

→ x : 90

→ By using cross multiplication

∵ x * 45 = 3 * 90

∴ 45x = 270

→ Divide both sides by 45 to find x

`\begin{gathered} \because(45x)/(45)=(270)/(45) \\ \therefore x=6 \end{gathered}`

∴ You need 6 minutes to do 90 sit-ups