PSLE
Archie threw a ring around the top of a bottle 30 times. One point was scored when the ring fit on the bottle and one point was deducted when the ring bounced off the bottle.

For Archie's first 25 throws, the ring fit on the bottle 20 times.

1. What was Archie's score from the first 25 throws?
2. At the end of 30 throws, Archie's scored 17 points. How many successful throws did he make for his last 5 throws?

(a)
Number of misses
= 25 - 20
= 5

Number of points scored = 20

Archie's score
= 20 - 5
= 15

(b)
Archie's score for the last 5 throws
= 17 - 15
= 2

If Archie made 5 successful throws, the score he earned = 5

If Archie made 4 successful throws, the score he earned
= 4 - 1
= 3

If Archie made 3 successful throws, the score he earned
= 3 - 1
= 2

Since Archie's score for the last 5 throws was 2, he made 3 successful throws.

Answer(s): (a) 15; (b) 3