Question

Page :
157
Ratio The ages of riya and rahul are
in the ratio 5:7.4 years ,
later, The sum of their ages will be
56 years, what are their present ages ?​

Answer 1

Answer:

20 and 28 year

Step-by-step explanation:

Let the present age of Riya be 5a

                              Rahul be 7a

After 4 year:

 Riya = 5a + 4

Rahul = 7a + 4

            Sum of ages is 56

⇒ (5a + 4) + (7a + 4) = 56

⇒ 5a + 7a + 4 + 4 = 56

⇒ 12a + 8 = 56

⇒ 12a = 56 - 8 = 48

⇒ a = 48/12 = 4

  Hence,

Age of Riya = 5a = 5(4) = 20 year

        Rahul = 7a = 7(4) = 28 year

Answer 2

AnsWer :

The present age of Riya and Rahul will 20 years and 28 years respectively.

Step-by-step explanation:

Let the age of riya be 5x and age of rahul be 7x.

After 4 years,

• Riya age will be 5x + 4
• Rahul age will be 7x + 4

_______________________

$</p><p>\underline{ \large \purple{ \mathscr{\bigstar \: \: \:A \bf{ccording} \: to \: \mathscr {Q} \bf{uestion} ....}}}$

$:\implies\sf (5x + 4) \: + \: (7x + 4) \: = \: 56$

$:\implies\sf 5x \: + \: 7x \: + \: 8 \: = \: 56$

$:\implies\sf 12x \: + \: 8 \: = \: 56$

$:\implies\sf 12x \: = \: 56 \: - \: 8$

$:\implies\sf 12x \: = \: 48$

$:\implies\sf x \: = \: \dfrac{48}{12}$

$:\implies \underline{ \boxed{\sf x \: = \: 4}}$

_____________________

$\bigstar \: \:\underline{\boldsymbol{Present\: Age\:of\: Riya\:\&\:Rahul:}}$

$</p><p>\bullet\:\:\textsf{Riya = 5x = 5(4) = \textbf{20 years}}$

$\bullet\:\:\textsf{Rahul = 7x \: = 7(4) = \textbf{28 years}}</p><p>$