Question

If the average (arithmetic mean) of 3a and 4b is less than 50, and a is twice b, what is the largest integer of a?
Select one:
a. 9
b. 11
c. 19
d. 20

Answer 1

a=2b 3a=6b
average of 3a and 4b is equal to average of 6b and 4b
6b+4b/2=5b 5b<50 then b<10
a=2b 2b<20 a<20 so the largest integer is 19.