Rahul's monthly income is * 25,000, out of which he spends 20% on accommodation,
50% on household expenditure, 15% on
transportation and the rest is saved. How
much money does he save?

3750

Step-by-step explanation:

25,000 = 100%

20% accomodation

50% household

15% transportation

Saved=100%-20%-50%-15%=15% left saved

15% of 25,000=3750

First you have to solve for one of the unknowns in one of the problems, then substitute it into the other problem to solve for the other unknown... Sound complicated?... Not really! Let me show you...

Let's take the first equation... we'll solve for x

x + y = 2
x = 2 - y 

Ok, now we have an expression for the value of x.  It's 2 - y.  So let's substitute it into the other equation.

3x + 2y = 5
3 (2 - y) + 2y = 5  distribute the 3 into the parentheses
6 -3y + 2y = 5  now lets solve for y.  We need to isolate it so subtract 6                              from both sides.
6 - 3y + 2y - 6 = 5 - 6  Now combine like terms
-y = -1
y = 1

Now we have a number value for y we can substitute it back into the 1st equation and find the number value of x

x + y = 2
x + 1 = 2
x = 1

So our answer is (1, 1)

Wasn't that easy!!