AP EAPCET 19-Aug-2021 Shift 1 Paper

3 different coins of denominations Rupee 1, 2,5 and 10.
Formula used:
‌nCr=

n!

[r!×(n−r)!]

Calculation:
There are 3 combinations to have the different sum of money
Any 1 coin at a time =‌3C1
⇒

3!

[1!×(3−1)!]

=3
Any 2 coins at a time =‌3C2
⇒

3!

[2!×(3−2)!]

=3
All 3 coins at a time =‌3C3
⇒3!\/[3!×(3−3)!]=1
Sum of all combination
⇒3+3+1=7
∴ Total 7 different sums of money can be form.