Question 15 Marks
Find the least 5-digit number which is exactly divisible by 20, 25, 30.
Answer
View full question & answer→Least five digit number = 10000
$\begin{array}{c|c}5&20,25,30\\\hline2&4,5,6\\\hline2&2,5,3\\\hline3&1,5,3\\\hline5&1,5,1\\\hline&1,1,1\end{array}$
LCM of 20, 25, 30 is 300.
But we want the least five digit number which is divisible by 20, 25, 30.
So, we will multiply the LCM by a number that makes it the least five digit number divisible by 20, 25, 30.
300 × 31 = 9300
300 × 32 = 9600
300 × 33 = 9900
300 × 34 = 10200
So, the least five digit number divisible by 20, 25, 30 is 10200.
$\begin{array}{c|c}5&20,25,30\\\hline2&4,5,6\\\hline2&2,5,3\\\hline3&1,5,3\\\hline5&1,5,1\\\hline&1,1,1\end{array}$
LCM of 20, 25, 30 is 300.
But we want the least five digit number which is divisible by 20, 25, 30.
So, we will multiply the LCM by a number that makes it the least five digit number divisible by 20, 25, 30.
300 × 31 = 9300
300 × 32 = 9600
300 × 33 = 9900
300 × 34 = 10200
So, the least five digit number divisible by 20, 25, 30 is 10200.












