Ralphy Boy deposits $100 in an annuity account each month which pays 7.5% interest compounded monthly. After 18 years what is the annuity worth?

Element x decays radioactively with a half life of 8 minutes. if there are 450 grams of element x, how long, to the nearest tenth of a minute, would it take the element to decay to 37 grams?

Prove that the sum of two consecutive exponents of the number 5 is divisible by 30.if two consecutive exponents are 5n and 5n + 1, then their sum can be written as 30.

Atreasure chest sinks at a rate no less than 20 feet er second. the floor of the icean is at most at -4,200 feet. will the tresure chest reach the ocean floor in less than 3 minutes? explain.