Question

Exercise 5

A bag of corn can feed 50 chickens for 12 days.
a) For how many days will the same bag feed 40 chickens?
b) How many bags of corn are needed to feed 20 chickens for 30 days?
2. Fifteen men build a wall in five days. How long will it take the following
number of men to build the wall?
al one man
b) 10 men
c) 20 men
3. A 3-year-old girl has six sisters. Her youngest sister is 4 years old.
a) How many sisters did she have when she was 1 year old?​

Answer 1

Explanation:

a) By proportion number of days = 12 * 50/40

= 15 days.

b) Finding the number of bags per day that 1 chicken needs:

50 chickens eat 1 bag in 12 days

so 50 chickens eat 1/12 of a bag in 1 day.

1 chicken eats 1/(12*50) of a bag in 1 day.

20 chickens for 30 days:

20 chickens eats 20(12*50) in 1 day

and in 30 days 20 eat 30*20 / (12*50)

= 1 bag.

2.

a) 5*15 = 75 days

b) (15/10) * 5 = 7 1/2 days.

c) (15/20) * 5 = 3 * 5 /4 = 3 3/4 days.

3. When she was 1 year old her youngest sister was 2 - she had the same number of sisters as when she was 3.

So the answer is 6.