Question

Doreen and Irena plan to leave their houses at the same time, roller blade towards each other, and meet for lunch after 2 hours on the road. Doreen can maintain a speed of 9 miles per hour, which is 90% of Irena's speed. If they meet exactly as planned, what is the distance between their houses?

Answer 1

38 miles

Explanation:

Given,

The speed of Doreen = 9 miles per hour,

Since,

`Speed = (Distance)/(Time)\implies Distance = Speed* Time`

So, the distance covered by Doreen in 2 hours = 9 × 2 = 18 miles,

∵ Doreen speed is 90% of Irena's speed.

I.e. 90% of Irana's speed = 9 miles per hour

`\implies (90)/(100)* \text{ Irana's speed}=9`

`\implies \text{Irana's speed}=(900)/(90)=10\text{ miles per hour}`,

Thus, the distance covered by Irana in 2 hours = 10 × 2 = 20 miles

Hence, the distance between their houses = distance covered by Doreen in 2 hours + distance covered by Irana in 2 hours

= 18 + 20

= 38 miles