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 17,51,85, 119,... Find the distance that the projectile traveled in the ninth second. (1 point) 306 ft. 323 ft. 255 ft. 289 ft.

Answer 1

The sequence is arithmetic with first term 17 and common difference 34. The nth term is 17 + (n−1)·34. For n = 9: 17 + 8·34 = 17 + 272 = 289 ft.