Question

At 1:30 Marlon left his house to go to the beach, a distance of 7.2 miles. He rode his skateboard until 2:15, then walked the rest of the way. He arrived at the beach at 3:00. Marlon's speed on his skateboard is 2 times his walking speed. Find his speed when walking and when skateboarding

Answer 1

walking speed: 3.2mph skateboarding speed: 6.4mph

Explanation:

Answer 2

Answer: The speed when walking = 3.2 miles per hour

The speed when skateboarding=2(3.2)=6.4 miles per hour

Explanation:

Let x be the walking speed then his speed on skateboard be 2x.

Time taken in skateboarding = 1:30-2:15= 45 minutes=3/4 hour

Distance traveled by skating is given by :-

`d_1=speed*time=2x((3)/(4))=(3)/(2)x`

Time taken for walking = 2:15-3:00=45 minutes=3/4 hour

Distance traveled by walking is given by :-

`d_2=speed*time=(3)/(4)x`

Distance between house and beach = 7.2 miles

`\\\Rightarrow\ d_1+d_2=7.2\\\Rightarrow\ (3)/(2)x+(3)/(4)x=7.2\\\\\Rightarrow\ (9)/(4)=7.2\\\Rightarrow\ x=(7.2*4)/(9)\\\Rightarrow\ x=3.2`

Hence, The speed when walking = 3.2 miles per hour

The speed when skateboarding=2(3.2)=6.4 miles per hour