George has these two options for contact lenses. Option A
Option B
£108 for 90 pairs
£1.15 each pair
George wants to buy 90 pairs of contact lenses.
He wants to pay as little as possible.
(b) Which option should George use?

The number if marbles of different colors stored in a hat is listed below: 4 red marbles 10 green marbles 7 blue marbles. without looking in the hat, dan takes out a marble at random. he replaces the marble and then takes out another marble from the hat. what is the probability that dan takes out a blue marble in both draws?

2.5 milligrams is equivalent to how many grams

Suppose a laboratory has a 30 g sample of polonium-210. the half-life of polonium-210 is about 138 days how many half-lives of polonium-210 occur in 1104 days? how much polonium is in the sample 1104 days later? 9; 0.06 g 8; 0.12 g 8; 2,070 g