math
posted by fei on .
9. If possible, change each comparison of red paint
to white paint to a percent comparison. If it is
not possible, explain why.
a. The fraction of a mix that is red paint is
b. The ratio of red to white paint in a different
mix is 2 to 5.
10. If possible, change each comparison to a fraction
comparison. If it is not possible, explain why.
a. The nut mix has 30% peanuts.
b. The ratio of almonds to other nuts in the mix is 1 to 7.

These kind of questions are often done incorrectly
9 a) missing information
b) if the ratio of red paint to white paint is 2 : 5
that means there are 2parts red and 5 parts white for a total of 7 parts
so the fraction of the paint which is red is 2/7
and 2/7 (100%) is appr 28.86%
10
a)30% or 30/100 or 3/10 of the mixture is peanuts
b) ratio of almonds to other nuts = 1 : 7
so the percentage of almonds in the mixture = 1/8(100%) = 12.5%
check:
suppose we have a 1000 g mixture
then amount of almonds = .125(1000) = 125 g
then amount of other nuts = 1000125 = 875 g
so the ratio of almonds : other nuts
= 125 : 875
= 1 : 7 
Misha has 8 cats. He gives away 8 how many does he have now?

In 1970, the total enrollment in public universities and colleges in a country was 5.7 million students. By 2004, enrollment had risen to 13.1 million students. Assume enrollment can be modeled by exponential growth.
(a) Estimate the total enrollments in 1980, 1990, and 2000. (Round your answers to one decimal place.)
1980 million
1990 million
2000 million
(b) How many years after 1970 until the enrollment doubles from the 2004 figure? (Round your answer to one decimal place.)
years
(c) By what percent is the enrollment increasing each year? (Round your answer to two decimal places.)
% 
The fraction of a mix that is red paint 1/4