A copper-lead alloy is in the ratio of four parts copper to seven parts
lead.
a If a block of this alloy contains 21 kg
of copper, how much lead is there?
Another block of the alloy weighs 2.64 kg.

What set does not contain -3 the set of all real numbers the set of all integers the set of all whole numbers the set of all rational numbers

After t seconds, a ball tossed in the air from the ground level reaches a height of h feet given by the equation h = 144t-16t^2. after how many seconds will the ball hit the ground before rebounding?

Which of the following is not a subset of {1,2,3}?