6 N + 4 P = 56
7 N + 5 P = 66
Fill in the blanks.
- 1 N = _____
- 1 P = _____
- 3 N + 3 P = _____
(a)
6 N + 4 P = 56 --- (1)
7 N + 5 P = 66 --- (2)
Make P the same.
LCM of 4 and 5 = 20
(1) x 5
30 N + 20 P = 280 --- (3)
(2) x 4
28 N + 20 P = 264 --- (4)
(a)
(3) - (4)
(30 N + 20 P) - (28 N + 20 P) = 280 - 264
30 N - 28 N + 20 P - 20 P = 16
2 N = 16
1 N = 16 ÷ 2 = 8
(b)
Substitute N = 8 into (1).
6 N + 4 P = 56
6 x 8 + 4 P = 56
48 + 4 P = 56
4 P = 56 - 48 = 8
1 P = 8 ÷ 4 = 2
(c)
3 N + 3 P
= 3 x 8 + 3 x 2
= 24 + 6
= 30
Answer(s): (a) 8; (b) 2; (c) 30
