1.

the numerator of a rational is less than its denominater by 4 .if the numerator is multiplied by 2 and the denominator is increased by 4 the number becomes 14/15. find the origanal number. ​

Answer»

Answer:-

Let the NUMBER be x/y.

Given:

NUMERATOR is less than the denominator by 4.

⟶ Numerator = Denominator - 4

⟶ x = y - 4 -- equation (1)

And,

If the numerator is MULTIPLIED by 2 and denominator is increased by 4 , the number becomes 14/15.

\longrightarrow \sf  \dfrac{2 \times x}{y + 4}   =  \dfrac{14}{15}

SUBSTITUTE the value of x from equation (1).

\: \longrightarrow \sf \:  \frac{2(y - 4)}{y + 4}  =  \frac{14}{15}  \\  \\ \longrightarrow \sf \:  \frac{2y - 8}{y + 4}  =  \frac{14}{15}  \\  \\ \longrightarrow \sf \: 15(2y - 8) = 14(y + 4) \\  \\ \longrightarrow \sf \: 30y - 120 = 14y + 56 \\  \\ \longrightarrow \sf \: 30y - 14y = 56 + 120 \\  \\ \longrightarrow \sf \: 16y = 176 \\  \\ \longrightarrow \sf \: y =  \frac{176}{16}  \\  \\ \longrightarrow \boxed{ \sf \: y = <klux>11</klux>}

Substitute the value of y in equation (1).

⟶ x = y - 4

⟶ x = 11 - 4

⟶ x = 7

∴ The required number x/y is 7/11.



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