Question : If a 10-digit number 75462A97B6 is divisible by 72, then the value of $\sqrt{8 A-4 B}$ is:
Option 1: $\sqrt{30}$
Option 2: $\sqrt{27}$
Option 3: $\sqrt{21}$
Option 4: $\sqrt{28}$
Latest: SSC CGL preparation tips to crack the exam
Don't Miss: SSC CGL complete guide
New: Unlock 10% OFF on PTE Academic. Use Code: 'C360SPL10'
Correct Answer: $\sqrt{28}$
Solution : A number is divisible by 72 if and only if it is divisible by both 8 and 9 (since 72 is the product of 8 and 9, and 8 and 9 are coprime). 1. For a number to be divisible by 8, its last three digits must form a number that is divisible by 8. In this case, the last three digits are 7B6. For 7B6 to be divisible by 8, "B" must be 3. 2. For a number to be divisible by 9, the sum of its digits must be divisible by 9. If we substitute B = 3 into the number 75462A9736, the sum of the digits = 7 + 5 + 4 + 6 + 2 + A + 9 + 7 + 3 + 6 = 49 + A For this to be divisible by 9, A must be 5. $\therefore\sqrt{8 A-4 B}=\sqrt{8 \times 5 - 4 \times 3} = \sqrt{28}$ Hence, the correct answer is $\sqrt{28}$.
Candidates can download this ebook to know all about SSC CGL.
Answer Key | Eligibility | Application | Selection Process | Preparation Tips | Result | Admit Card
Question : If a nine-digit number 789x6378y is divisible by 72, then the value of xy is:
Question : If the five-digit number 235xy is divisible by 3,7 and 11, then what is the value of (3x - 4y)?
Question : If the 8-digit number 123456xy is divisible by 8, then the total possible pairs of (x, y) are:
Question : A 9-digit number $846523X7Y$ is divisible by 9 and $Y - X = 6$. Find the value of $\sqrt{2X+4Y}$.
Question : If $y=1+\sqrt{3}+\sqrt{4}$, then the value of $2 y^4-8 y^3-6 y^2+28 y-84$ is:
Regular exam updates, QnA, Predictors, College Applications & E-books now on your Mobile