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 = 190 g
(b)
Mass of P and R
= 500 - 190
= 310 g
Mass of P and Q
= 540 - 190
= 350 g
Mass of Q and R
= 490 - 190
= 300 g
(P + R) + (P + Q) + (Q + R) = 310 + 350 + 300
2 P + 2 Q + 2 R = 960
2 x (P + Q + R) = 960
P + Q + R
= 960 ÷ 2
= 480 g
Average mass of the objects P, Q and R
= 480 ÷ 3
= 160 g
Answer(s): (a) 190 g; (b) 160 g