Question

A Robin can fly 10 miles per hour faster than a blue jay .It takes a Robin 1 1/2 hours to fly 45 mileshow many hours will it take a blue hay to fly that same distance

Answer 1

`\begin{gathered} \text{let:} \\ vr=\text{robin speed} \\ vb=\text{blue jay speed} \\ vr=vb+(10mi)/(h) \\ vb=vr-(10mi)/(h) \end{gathered}`

It takes a Robin 1 1/2 hours to fly 45 miles:

`\begin{gathered} d=v\cdot t \\ 45=vr\cdot t \\ 45=vr\cdot1.5 \\ vr=(45)/(1.5) \\ vr=(30mi)/(h) \end{gathered}`

Since:

`\begin{gathered} vb=vr-(10mi)/(h) \\ vb=(20mi)/(h) \end{gathered}`
`\begin{gathered} t=(d)/(v) \\ t=(d)/(vb) \\ t=(45)/(20) \\ t=2.25h \end{gathered}`