THE FARMER HAS FEMALE SHEEP AND LAMBS (CAMBRIDGE PAST PAPER)
The
farmer has 20 female sheep.
Each sheep has 0, 1, 2 or 3 lambs.
The table shows this information.
Mathematics
Cambridge IGCSE Test (0580 m16 qp 32)
i) Calculate the mean number of lambs per
sheep.
Answer:
Mean
number of lambs per sheep is
=
( 0x1 + 1x4 + 2x12 + 3x3 ) lambs divided by total sheep
=
( 0x1 + 1x4 + 2x12 + 3x3 ) lambs / 20 sheep
= 1.85
ii) The farmer takes 1 lamb away from each
of the sheep with 3 lambs.
These
lambs are given to 3 of the 4 sheep that have 1 lamb.
Complete
the table after the farmer has done this.
Answer:
1 lamb is taken away from each of the sheep with 3 lambs. So there is no sheep which has 3 sheep.
Then for every 1 lamb which is already taken, will be given to the sheep which only has 1 lamb.
So only one sheep which has 1 lamb.
Finally, the sheep which has 2 lambs are 18 sheeps.
(iii) Explain why the mean number of lambs per sheep does not change.
Answer:
Same total number of sheep and same
total number of lambs.
