A person X has four notes of Rupee 1, 2, 5 and 10 denomination. The number of different sums of money she can form from them is

Explanation

We can solve this problem by listing out all possible combinations of the given denominations. Using only one note at a time, we can form the following sums: 1, 2, 5, 10 Using two notes at a time, we can form the following sums: 1+1=2, 1+2=3, 1+5=6, 1+10=11, 2+2=4, 2+5=7, 2+10=12, 5+5=10, 5+10=15 Using three notes at a time, we can form the following sums: 1+1+1=3, 1+1+2=4, 1+1+5=7, 1+1+10=12, 1+2+2=5, 1+2+5=8, 1+2+10=13, 1+5+5=11, 1+5+10=16, 2+2+5=9, 2+2+10=14, 2+5+5=12, 2+5+10=17, 5+5+10=20 Using all four notes, we can form only one sum: 1+2+5+10=18 Therefore, the total number of different sums of money that can be formed using these notes is 15. Answer: 15.