Question
If a nine-digit number 389x6378y is divisible by 72,
then the value of √(6x + 7y) will be∶Solution
Divisibility law of 8 ⇒ A number divisible by 8 if its last three digits are divisible by 8. Divisibility law of 9 ⇒ A number is divisible by 9 if sum of its digit is divisible by 9. Nine-digit number 389x6378y is divisible by 72, so number also divisible by 8 and 9 also. 78y divisible by 8 if y = 4 so number become 389x63784 Nine-digit number 389x63784 divisible by 9 if sum of its digit divisible by 9. ⇒ 3 + 8 + 9 + x + 6 + 3 + 7 + 8 + 4 ⇒ 48 + x If we put x = 6, the number become 54 which is divisible by 9. So, x = 6 and y = 4 Now, √(6x + 7y) ⇒ √(6 × 6 + 7 × 4) ⇒ √(36 + 28) ⇒ √64 ⇒ 8
Find the simplified value of the given expression:
1.82 + 2.42 + 1.52 - 1.8 x 2.4 - 2.4 x 1.5 - 1.8 x 1.5
26% of 650 + 15% of 660 – 26% of 450 = ?
2/5 of 3/4 of 7/9 of 7200 = ?
What are the values of k, if the roots of the equation x² + 2(k - 4)x + 2k = 0 are equal?
√196 + (0.25 × 144) + 19 = ? + 72
- What will come in place of (?), in the given expression.
75% of 640 – 20% of 150 = ? 116 x (2/3)% of 420 + 666 x (2/3)% of 186 = 457 x (1/7)% of 126 + 555 x (5/9)% of 198 + ?
(3500 ÷ √1225) × √(20.25) = ? ÷ 4
(25)² × 4 ÷ 5 + (3)³ + 48=? + 425
18 × √225 + 378 ÷ √441 = ? × 9