Hi syiro,
First you have to thoroughly read through and understand the material, so first you have to find the 3 equation.
first paragraph (in english) u gotta find the equation for the total number of houses sold of each kind equals to the capital
1: 3A+5B+6C=630
on the 2nd line of the 2nd paragraph (in english)
2: A+B+C=140
thrid paragraph, here it says the profit, so in order to get the profit of each house, you gotta take the selling price of each house minus off the construction costs so,
3:A(5.53) + B(93) + C(116) = 515
A+B+C=140
3A+5B+6C=630
A(5.53) + B(93) + C(116) = 515
so from these 3 equation, Im pretty sure you know how to do from that on, try it out
Good Luck with that. Hope that helps.
Hey @syiro
Let’s denote the number of units sold for each type of house as follows:
 Let ( x ) be the number of units of Type A houses sold.
 Let ( y ) be the number of units of Type B houses sold.
 Let ( z ) be the number of units of Type C houses sold.
Given that the total construction cost is RM 630 million and the total profit is RM 515 million, we can set up the following equations:

Construction Cost Equation:
[ 3x + 5y + 6z = 630 ] 
Profit Equation:
[ 140x + 140y + 140z = 515 ]
Now, we’ll solve these equations simultaneously to find the values of ( x ), ( y ), and ( z ).
From the first equation, we can rewrite it as:
[ x = (630  5y  6z) / 3 ]
Substitute this expression for ( x ) into the second equation:
[ 140((630  5y  6z) / 3) + 140y + 140z = 515 ]
After solving for ( y ) and ( z ), you can then find ( x ) using any of the original equations.
hope the above will be helpful.
@Henry