Advertisements
Advertisements
Question
Three bells toll at intervals of 9, 12 and 15 minutes respectively. If they start tolling together, after what time will they next toll together?
Advertisements
Solution
It is given that three bells toll at the intervals of 9, 12, and 15 minutes, respectively.
We need to find out if they start tolling together and after what time they will next toll together.
LCM of 9, 12, 15 can be found as:
On doing factorization of 9, 12 and 15, we get,
9 = 32
12 = 22 × 3
15 = 5 × 3
LCM can be written as = 32 × 22 × 5 = 180
Time = 180 minutes = 3 hours
APPEARS IN
RELATED QUESTIONS
Consider the number 12n where n is a natural number. Check whether there is any value of n ∈ N for which 12n ends with the digital zero.
Find the LCM and HCF of the following integers by applying the prime factorisation method.
12, 15 and 21
Check whether 6n can end with the digit 0 for any natural number n.
Can two numbers have 16 as their HCF and 380 as their LCM? Give reason.
Write down the decimal expansions of the following rational numbers by writing their denominators in the form 2m × 5n, where, m, n are non-negative integers.\[\frac{13}{125}\]
Write down the decimal expansions of the following rational numbers by writing their denominators in the form 2m × 5n, where, m, n are non-negative integers.\[\frac{129}{2^2 \times 5^7}\]
Find the greatest number consisting of 6 digits which is exactly divisible by 24, 15, 36?
n2 – 1 is divisible by 8, if n is ______.
If the HCF of 65 and 117 is expressible in the form 65m – 117, then the value of m is ______.
Statement A (Assertion): If product of two numbers is 5780 and their HCF is 17, then their LCM is 340.
Statement R (Reason): HCF is always a factor of LCM.
