Question

5. A study of a population of 1,200 frogs revealed that 12 out of every 180 frogs in the population

have spots on their back. Based on the results of this study, how many frogs in the population do
NOT have spots on their back?
A. 80 C. 1,280
B. 168 D. 1,120

Answer 1

1,280

Explanation:

prob(spots) = 12/180 = 1/15

so of the 1200 frogs, (1/15)(1200) should have spots, so ..

how many should not have frogs ?

or

prob(not spots) = 14/15

number who don't have spots = (14/15)(1200) = 1,280