6 V + 4 W = 54
7 V + 5 W = 65
Fill in the blanks.
- 1 V = _____
- 1 W = _____
- 3 V + 3 W = _____
(a)
6 V + 4 W = 54 --- (1)
7 V + 5 W = 65 --- (2)
Make W the same.
LCM of 4 and 5 = 20
(1) x 5
30 V + 20 W = 270 --- (3)
(2) x 4
28 V + 20 W = 260 --- (4)
(a)
(3) - (4)
(30 V + 20 W) - (28 V + 20 W) = 270 - 260
30 V - 28 V + 20 W - 20 W = 10
2 V = 10
1 V = 10 ÷ 2 = 5
(b)
Substitute V = 5 into (1).
6 V + 4 W = 54
6 x 5 + 4 W = 54
30 + 4 W = 54
4 W = 54 - 30 = 24
1 W = 24 ÷ 4 = 6
(c)
3 V + 3 W
= 3 x 5 + 3 x 6
= 15 + 18
= 33
Answer(s): (a) 5; (b) 6; (c) 33