Book Maths Puzzle Numerical Ability

how many terms of series 5+7+9....... must be taken in order that the sum may be 480?

Read Solution (Total 2)

20
using te sum of AP n/2*(2a+(n-1)d)
here a=5 ;d=2.so solve
10 years agoHelpfull: Yes(1) No(0)

a=5
d=2
sum=n/2(2a+(n-1)d)=480

n/2(2*5+(n-1)2)=480
n=20
10 years agoHelpfull: Yes(0) No(0)

Book Other Question

p and a do work in 40 and 25 days.they work together but p left after some days and a finish remaining work in 12 days. after how many days did p leave?

ans:8days 90,180,12,50,100,200,__,3,50,4,25,2,6,30,3? what is the missing number?