1. In how many ways can a person use all the four heaters in a four -day period?
a.
4
b.
88
c.
16
d.
10
e.
12
2. If heater S is used on the third day and different heaters are used on the first and fourth days, then which heater is used on the first day?
a.
P
b.
Q
c.
R
d.
S
e.
cannot be determined