Question

A large asteroid crashed into a moon of another planet causing several boulders from the moon to be propelled into space toward the planet. Astronomers were able to measure the speed of one of the projectiles. The distance (in feet) that the projectile traveled each second, starting with the first second, was given by the arithmetic progression 18,54, 90,126, . Find the distance that the projectile traveled in the eighth second.

Answer 1

270 feet

Explanation:

From the sequence given, we can see that the asteroid travels 36 feet more with each second. (as seen
`54-18=36` and
`90-54=36` etc.)

So 5th second, it will travel:
`126+36=162`

6th second, it will travel:
`162+36=198`

7th second, it will travel:
`198+36=234`

8th second, it will travel:
`234+36=270`

Hence, in the eighth second, the projectile traveled 270 feet.