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Problem 7

Anita jogs at a constant speed of 4 miles per hour. Anita's brother leaves their house 12 minutes after

her, and he catches up to her 24 minutes later. If Anita's brother is also running at a constant rate, what is

his speed, in miles per hour?

User Zmorris
by
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1 Answer

6 votes

Answer:

6 miles per hour

Explanation:

Anita's speed is given as = 4 miles per hour

We are told in the question that:

Anita's brother leaves their house 12 minutes after her, and he catches up to her 24 minutes later.

Hence, total time for Anita's jogging =

12minutes + 24 minutes = 36 minutes

Converting to hour

60 minutes = 1 hour

36 minutes =

Cross Multiply

36/60 hr = 3/5 hr

Since Anita's speed is 4 mph,

The formula for distance = Speed × Time.

The total distance Anita covers when jogging = 4mph × 3/5 hour

= 12/5miles

We are told in the question that:

Anita's brother is also running at a constant rate

Hence

The distance Anita's brother is covering = 12/5 miles as well

The time the brother runs = 24 mins

Convert to hour

60 minutes = 1 hour

24 minutes =

Cross Multiply

24/60 hour = 6/15 hour

Anita's brother's speed =

Distance/time

= 12/5 miles ÷ 6/15 hour

= 12/5 × 15/6

= 6 miles per hour.

Therefore, Anita's brother's speed is 6 miles per hour

User Spiros
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