8 T + 4 U = 52
9 T + 5 U = 60
Fill in the blanks.
- 1 T = _____
- 1 U = _____
- 2 T + 2 U = _____
(a)
8 T + 4 U = 52 --- (1)
9 T + 5 U = 60 --- (2)
Make U the same.
LCM of 4 and 5 = 20
(1) x 5
40 T + 20 U = 260 --- (3)
(2) x 4
36 T + 20 U = 240 --- (4)
(a)
(3) - (4)
(40 T + 20 U) - (36 T + 20 U) = 260 - 240
40 T - 36 T + 20 U - 20 U = 20
4 T = 20
1 T = 20 ÷ 4 = 5
(b)
Substitute T = 5 into (1).
8 T + 4 U = 52
8 x 5 + 4 U = 52
40 + 4 U = 52
4 U = 52 - 40 = 12
1 U = 12 ÷ 4 = 3
(c)
2 T + 2 U
= 2 x 5 + 2 x 3
= 10 + 6
= 16
Answer(s): (a) 5; (b) 3; (c) 16
