question_answer

           If \[4a+5y=83\]and \[\frac{3a}{2b}=\frac{21}{22},\]then find the value of\[b-a\]

A) 11                                

B)  7      

C)  4

D)  3

Correct Answer: C

Solution :

According to the question, \[4a+5b=83\]                            ...(i) and   \[\frac{3a}{2b}=\frac{21}{22}\Rightarrow \frac{a}{b}=\frac{7}{11}\]    \[\Rightarrow \]    \[11a-7b=0\]                             ...(ii) By solving Eq. (i) and Eq. (ii), we get \[b=\frac{913}{83}\]and\[a=7\]             \[\therefore \]\[b-a=11-7=4\]