Question

How many multiples of 5 lie between 15 and 350

Answer 1

Answer:

here we have to find number which lie between 15 and 350 which is multiple of 5 .

therefore we take the multiple of 5

that is 5,10,15,20,25,............to infinity term

but here given multiple between 15 and 350

so

here 1st multiple is 15

then second is 20 and

so on

but last multiple that lie between 15 and 350 is 350 because 350 is divisible by 5.

now

let a=15

and a2=20 because it is the second multiple of 5 that lie between 15 and 350

and let d=common difference

as we know d=a2-a=20-15=5

in this question last number is 350

therefore we know that

last number

=a+(n-1)×d

here n=number of term

so

a.t.q

350=15+(n-1)5

350-15=(n-1)5

335=(n-1)5

335÷5=(n-1)

n-1= 67

n=67+1

n=68

therefore 68 number that lie between 15 and 350 which is multiple of 5

this is the required answer