Question

If the product of two numbers is 320 and their ratio 1:5, then the sum of these two numbers is
(a) 42
(b) 48
(c) 44
(d) 40

Answer 1

Let the numbers are ( x ) and ( 5x )

Given, their product = 320

x × 5x = 320

$\rightarrow5 {x}^{2} = 320 \\ \\ \rightarrow \: {x}^{2} = \frac{320}{5} \\ \\ \rightarrow {x}^{2} = 64 \\ \\ x = 8 \: \: or \: \: - 8$

Sum of numbers [ taking negative values ]

x + 5x
=> ( - 8 ) + 5( - 8 )
=> -48

Sum of numbers [ taking positive values ]

=> x + 5x
=> 8 + 5(8)
=> 48





Neglect negative value, their sum = 48



Option ( B ) is correct

Answer 2

x*5x=320
5x²=320
x²=64
x=8,-8

now,

8+5*8=8+40=48.