7 V + 3 W = 32
8 V + 4 W = 40
Fill in the blanks.
- 1 V = _____
- 1 W = _____
- 3 V + 3 W = _____
(a)
7 V + 3 W = 32 --- (1)
8 V + 4 W = 40 --- (2)
Make W the same.
LCM of 3 and 4 = 12
(1) x 4
28 V + 12 W = 128 --- (3)
(2) x 3
24 V + 12 W = 120 --- (4)
(a)
(3) - (4)
(28 V + 12 W) - (24 V + 12 W) = 128 - 120
28 V - 24 V + 12 W - 12 W = 8
4 V = 8
1 V = 8 ÷ 4 = 2
(b)
Substitute V = 2 into (1).
7 V + 3 W = 32
7 x 2 + 3 W = 32
14 + 3 W = 32
3 W = 32 - 14 = 18
1 W = 18 ÷ 3 = 6
(c)
3 V + 3 W
= 3 x 2 + 3 x 6
= 6 + 18
= 24
Answer(s): (a) 2; (b) 6; (c) 24