Question

by what rational number should- 12 1/2 be divided to get 1 7/8

Answer 1

Heya !!



-12 1/2 = -25/2


And,


1 7/8 = 15/8


Let -25/2 should be divided by X to get 15/8 .



Therefore,



-25/2 ÷ X = 15/8




-25/2 × 1/X = 15/8




-25/2X = 15/8





2X × 15 = -25 × 8




2X = ( -25 × 8 / 15 )



X = ( -25 × 8 / 2 × 15 )


X = (-5 × 4 )/ ( 3 ) = -20/3



Hence,


-25/2 should be divided by -20/3 to get 15/8.

Answer 2

Let the required number be x
According to the question
$- 12 \frac{1}{2} \div x = 1 \frac{7}{8} \\ \frac{ - 25}{2} \div x = \frac{15}{8} \\ \frac{ - 25}{2} \times \frac{1}{x} = \frac{15}{8} \\ \frac{1}{x } = \frac{15}{8} \times \frac{ - 2}{25} \\ \frac{1}{x} = \frac{ - 3}{20} \\ x = \frac{ - 20}{3} \\ x = - 6 \frac{2}{3}$