Question

a sum of money deposited in a bank for a period of 5 years at 5%p.a simple interest earns an interest of Rs 3125.find the sum.

Answer 1

i think ds may be the right ans

Answer 2

Answer:

Step-by-step explanation:

Multiples of 2: 2;4;...........100

Multiples of 5: 5;10..........100

In the above series some numbers are repeated twice these are multiples of 10 i.e LCM of 2 and 5

Sum of integers which are divisible by 2 and 5 from 1 to 100=

(Sum of integers which are divisible by 2 from 1 to 100) + (sum of integers which are divisible by 5 from 1 to 100) -(sum of integers which are divisible by 10 from 1 to 100) =

(2+4+......... +100) +(5+10+...... +100) -(10+20+...... 100)

=2(1+2+3+....... 50) + 5(1+2+3+.......20) -10(1+2+3+..... +10) =

2(50(50+1)) ÷2 + 5(20(20+1)) ÷2 -10(10(10+1)) ÷2

=(50(51)) +5(10(20+1) -5(10(11) =

50(51) +5(10(21)-5(10(11) =

2550+1050-550=

3600-550

=3050

Therefore sum of integers from 1 to 100 which are divisible by 2 or 5 is 3050