Replace variables with values and evaluate using order of operations:
D = WT2
W = 70
T = 4

At least two people have the same birthday in a school of 150 students

Bob the builder is making 480kg of cement mix. this is made by cement, sand and gravel in the ratio 1: 3: 4

1. if events a and b are non-overlapping events, how do you find the probability that one or the other occurs? 2. what does it mean if p(a or b) equals 1?