8 G + 3 H = 68
9 G + 4 H = 79
Fill in the blanks.
- 1 G = _____
- 1 H = _____
- 3 G + 4 H = _____
(a)
8 G + 3 H = 68 --- (1)
9 G + 4 H = 79 --- (2)
Make H the same.
LCM of 3 and 4 = 12
(1) x 4
32 G + 12 H = 272 --- (3)
(2) x 3
27 G + 12 H = 237 --- (4)
(a)
(3) - (4)
(32 G + 12 H) - (27 G + 12 H) = 272 - 237
32 G - 27 G + 12 H - 12 H = 35
5 G = 35
1 G = 35 ÷ 5 = 7
(b)
Substitute G = 7 into (1).
8 G + 3 H = 68
8 x 7 + 3 H = 68
56 + 3 H = 68
3 H = 68 - 56 = 12
1 H = 12 ÷ 3 = 4
(c)
3 G + 4 H
= 3 x 7 + 4 x 4
= 21 + 16
= 37
Answer(s): (a) 7; (b) 4; (c) 37
