Evaluate 20 - bc if b = 2 and c = 7

Acertain population of bacteria demonstrates exponential growth doubles in size every 4 days. how long will it take the population to triple in size?

Tabby sells clothing at a retail store, and she earns a commission of 6.25% on all items she sells. last week she sold a pair of jeans for $32.50, a skirt for $18.95, and 2 blouses for $14.95 each. what was tabby's total commission? a $4.15 b $5.08 c $81.35 d $348.60

Zach spent 2/3 hour reading on friday a 11/3 hlurs reading on saturday. how much more time did he read on saturday tha on friday