Question

1) One fifth of the sum of two angles is 36° and half of the difference between the two angles is 40°. Find the size of the two angles.

6) The price of 6 chairs and 3 tables is RM480. The price of 8 chairs and a table is RM400. Find the price of a chair and a table.
7) The sum of Wan Yee's and her mother's age is 60. Two years ago, her mother was three times older than Wan Yee. Calculate (a) Wan Yee's age now.
(b) her mother's age when she was born.​

Answer 1

1) 130 degrees and 50 degrees 6) a price of a chair is 40, a price of the table is 80 7) a) 16 b)28

Explanation:

1) Let it be that the first angle is x, The second one is y

1/5(x+y)=36- the first equation

1/2(x-y)=40- the second equation

The equations are simultaneous

x+y=180 and x-y=80

x+y+x-y=180+80

2x=260

x=130

y=50

6) The cost of a chair is x, the cost of table is y

6x+3y=480 2x+y=160

8x+y=400

8x+y- (2x+y)=400-160

6x=240

x=40

2*40+y=160

y=80

7) The Wan's age is x, the mother's age is y

x+y=60 x=60-y

Two years ago mother's age was y-2, when Wan;s age was x-2

y-2=(x-2)*3

y-2= (60-y-2)*3

y-2= (58-y)*3

y-2=174-3y

4y=176

y= 44

x=60-44=16- Wan's age now

44-16=28- her mother's age when she was born