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HCF and LCM of two numbers are 7 and 140 respectively. If the numbers are between 20 and 45, the sum of the numbers is :
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- 70
- 77
- 63
- 56
Correct Option: C
Let the numbers be 7p and 7q where p and q are co-prime.
Now, LCM of 7p and 7q = 7pq
∴ 7pq = 140
| ⇒ pq = | = 20 | 7 |
Now, required values of p and q whose product is 20 and are co-prime, will be 4 and 5.
∴ Numbers are 28 and 35 which lie between 20 and 45.
∴ Required sum = 28 + 35 = 63.
