PSLEThe graph shows the mass of a glass when empty and when different combinations of objects P, Q and R are placed in the glass.
- What is the mass of the empty glass?
- What is the average mass of the objects P, Q and R?
(a)
Mass of the empty glass = 140 g
(b)
Mass of P and R
= 430 - 140
= 290 g
Mass of P and Q
= 470 - 140
= 330 g
Mass of Q and R
= 420 - 140
= 280 g
(P + R) + (P + Q) + (Q + R) = 290 + 330 + 280
2 P + 2 Q + 2 R = 900
2 x (P + Q + R) = 900
P + Q + R
= 900 ÷ 2
= 450 g
Average mass of the objects P, Q and R
= 450 ÷ 3
= 150 g
Answer(s): (a) 140 g; (b) 150 g