Amna and Aliya have a total of Rs. 76. After Amna spends Rs.3.24 on an eraser, she is left with 3 times as much money as Aliya. How much does Aliya have?

Answer 1

Anna-3.24=3*Aliya but
Anna+Aliya=76

Anna-3*Ailya=-3.24 and
Anna+Alya=76
subtracting the second equation from the fidrst.
-4*Ailya=-79.24
Ailya= 19.81 Rs

Answer 2

Anna: $X.
Aliya: $Y.
Eq1: x + y = 76.

x-3.24 = 3y
Eq2: x-3y = 3.24.
Multiply Eq1 by 3 and add the Eqs:
3x + 3y = 228
x - 3y = 3.24
sum: 4x = 231.24
X = 57.81.
In Eq1, replace X with 57.81 and solve for Y.