A Bank advances Rs. 7850 for 7 months @ 8.5 per annum simple interest. What sum will have to be repaid at the end of this period ?
Answers
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