Question 959805
the average age of 4 brother is
12 years. if tha age of their mother is also
included the average is increased by 5 years
.tha age of the mother is?
average age  of 4 brothe is  12 yrs 
average =total age/number 
12=total age /4
total age of 4 brothers =12x4 =48 yrs  (let mother age is x)
total age  of brothers and mother will be =48+x
new average will be 12+5=17
avrage =toal age/number
17=48+x/5
17x5=48+x
85-48=x
x=37 yrs 
mother age is 37 yrs