RRB Group-D Model Paper 14 with answers for online practice

GIVEN:
The ratio of three numbers = 4 ∶ 3 ∶ 7
CALCULATION:
Let the numbers be 4x, 3x and 7x
According to question,
${\left(4\mathit{x}\right)}^2+{\left(3\mathit{x}\right)}^2+{\left(7\mathit{x}\right)}^2$ = 666
⇒ $16{\mathit{x}}^2+9{\mathit{x}}^2+49{\mathit{x}}^2$ = 666
⇒ $74{\mathit{x}}^2$ = 666
⇒ ${\mathit{x}}^2$ = 9
⇒ x = 3
∴ Largest number = 7x = 7 × 3 = 21