2023 · Q45
If x and y are two-digit prime numbers such that y is obtained from x by interchanging its digits and x − y = 36, then what is the value of xy?
general-mental-abilityquantitative-aptitude
- A1611
- B2701
- C4031
- D5603
Explanation
Write x = 10a+b and y = 10b+a; then x-y = 9(a-b) = 36, so a-b = 4. Among two-digit primes whose digits differ by 4, x = 73 and y = 37 satisfy the condition, since 73-37 = 36 and 37 is the digit-interchange of 73. Their product is 73 x 37 = 2701. Hence option B.