maths
posted by RS on .
1).Last year, a shopkeeper sold an average of 7 cartons of apples from january to april. He sold an average of 9 cartons of apples from june till end of the year. What is the total number of cartons he sold in the 11 months? if each carton contains 66 apples,what is the average number of apples sold per month?
2) Ameter records voltages between 0 volts and 20 volts. If the average value for three readings on the meter was 16 volts, what is the smallest possible reading, in volts?
3) The average of a set of 50 numbers is 38. The numbers of the set, namely 45 and 55 are discarded. What is the average of the remaining set of numbers?

1)
4 months @ 7 = 28 cartons
8 months @ 9 = 72 cartons
(assuming the year has 12 months instead of 11)
average apples sold per month is 100*66/12 = 550
2)
since the sum is 48, and no single reading is over 20, then the smallest must be at least 8.
3)
sum of numbers is 50*38 = 1900
new sum, less discarded values = 1800
new average is 1800/48 = 37.5