Solution:
Assuming 6 legs for each insect, 22 insects will have 132 legs.
But, there are 142 − 132 = 10 extra legs.
It is important to note that spiders have 8 legs and flies have 6 legs. So, there are 2 extra legs per spider on the web.
Thus, the 10 extra legs belong to 5 spiders.
Alternative Solution through Equations:
Let
s be the number of spiders and
f be the number of flies. Then,
s +
f = 22; and
8
s + 6
f = 142.
On solving the above two equations, we get
8
s + 6 (22 −
s) = 142; or
2
s = 142 − (6 × 22).
Thus,
s = 5.
Food for thought:
Wish to try another puzzle similar in concept to this one?
Then click here.