7 V + 3 W = 77
8 V + 4 W = 92
Fill in the blanks.
- 1 V = _____
- 1 W = _____
- 5 V + 3 W = _____
(a)
7 V + 3 W = 77 --- (1)
8 V + 4 W = 92 --- (2)
Make W the same.
LCM of 3 and 4 = 12
(1) x 4
28 V + 12 W = 308 --- (3)
(2) x 3
24 V + 12 W = 276 --- (4)
(a)
(3) - (4)
(28 V + 12 W) - (24 V + 12 W) = 308 - 276
28 V - 24 V + 12 W - 12 W = 32
4 V = 32
1 V = 32 ÷ 4 = 8
(b)
Substitute V = 8 into (1).
7 V + 3 W = 77
7 x 8 + 3 W = 77
56 + 3 W = 77
3 W = 77 - 56 = 21
1 W = 21 ÷ 3 = 7
(c)
5 V + 3 W
= 5 x 8 + 3 x 7
= 40 + 21
= 61
Answer(s): (a) 8; (b) 7; (c) 61
