Question

How many numbers between 40 and 70 are divisable by 4

Answer 1

$\bf\green{QuestioN:-}$

How many numbers between 40 and 70 are divisable by 4 ?

$\bf\red{AnsweR:-}$

First number is 40.

Last number given as 70.

The first term between 40 & 70 that is divisible by 4 is 44.

70 is not divisible by 4.

$\longrightarrow\bf\dfrac{70}{4}=17}$

$\longrightarrow\bf{17\times4=68}$

Then, 2 is the remainder here.

If we consider this as an AP, then

A = 44

L = 68

D = 4

$\longrightarrow\bf{L=A_n}$

$\longrightarrow\bf{A_n=a+(n-1)d}$

$\longrightarrow\bf{68=44+(n-1)4}$

$\longrightarrow\bf{68-44=4n-4}$

$\longrightarrow\bf{24=4n-4}$

$\longrightarrow\bf{24+4=4n}$

$\longrightarrow\bf{\dfrac{28}{4}=n}$

∴ n = 7.

Then there are 7 terms, that is divisible by 4 between 40 and 70.

All Done !!☺