PSLEThe graph shows the mass of a glass when empty and when different combinations of objects Q, R and S are placed in the glass.
- What is the mass of the empty glass?
- What is the average mass of the objects Q, R and S?
(a)
Mass of the empty glass = 140 g
(b)
Mass of Q and S
= 420 - 140
= 280 g
Mass of Q and R
= 350 - 140
= 210 g
Mass of R and S
= 430 - 140
= 290 g
(Q + S) + (Q + R) + (R + S) = 280 + 210 + 290
2 Q + 2 R + 2 S = 780
2 x (Q + R + S) = 780
Q + R + S
= 780 ÷ 2
= 390 g
Average mass of the objects Q, R and S
= 390 ÷ 3
= 130 g
Answer(s): (a) 140 g; (b) 130 g