An element with a mass of 570 grams decays by 26.7% per minute. To the nearest minute, how long will it be until there are 40 grams of the element remaining?

Offering 30 if a plus b plus c equals 68 and ab plus bc plus ca equals 1121, where a, b, and c are all prime numbers, find the value of abc. the answer is 1978 but i need an explanation on how to get that.

1) what is the measure of the exterior angle, ∠uvw ? 2) in triangle man, what is the measure of the exterior angle at n (in degrees)?

This is about circle theorems. someone asap : (