UPSC Government Jobs Exams

A person has 4 coins each of different denomination. What is the number of different sums of money the person can form (using one or more coins at a time)? [UPSC 2009(CS-P)]
a) 16
b) 15
c) 12
d) 11

Read Solution (Total 3)

through an example
suppose we take coin of denomination 1,2,5,10
by taking these
first we take 4 diffrent
then 1+2 =3, 1+5=6;1+10=11
then 2+5=7; 2+10=12
then 5+10=15
then take three coin
1+2+5=8; 1+2+10=13;2+5+10=17;1+5+10=16
then 1+2+5+10=18
total diffrent sums are 15
9 years agoHelpfull: Yes(2) No(1)

Manually,answer is coming to 15 but what is the way to do this? Using factorials or something similar?
9 years agoHelpfull: Yes(1) No(0)
4c1+4c2+4c3+4c4=15
7 years agoHelpfull: Yes(1) No(0)

UPSC Other Question

A man fills a basket with eggs in such a way that the number of eggs added on each successive day is the same as the number already present in the basket. This way the basket gets completely filled in 24 days. After how many days the basket was 1 / 4th full? [UPSC 2010 (CS-P)]
a) 6
b) 12
c) 17
d) 22 A person traveled a distance of 50 km in 8 hours. He covered a part of the distance on foot at the rate of 4 km per hour and a part on a bicycle at the rate of 10 km per hour. How much distance did he travel on foot?[UPSC 2010 (CS-P)]
a) 10 km
b) 20 km
c) 30 km
d) 40 km