Thursday, September 9, 2010

Fraction P6 2010 SA2 Pei Chun P2 Q17

In 2007, there were 90 more girls than boys in ABC School. In 2008, there were 1/3 fewer girls and the number of boys increased by 5/9, resulting in a total of 660 pupils. (a) What fraction of the pupils in 2007 were boys? Express your answer in its simplest form. (b) In 2009, the number of girls increased while the number of boys remained the same as in 2008. The ratio of the number of girls to the number of boys in 2009 was the same as the ratio in 2007. How many pupils were there in 2009? [5 marks][Answer given: 3/7, 980]

2007
G [][][][][][][][][][      90     ]
B [][][][][][][][][]

2008
G [][][][][][][   60   ]               ] 660
B [][][][][][][][][][][][][][]      ] pupils

20 u --> 660 - 60 = 600
1 u --> 600/20 = 30

9 u --> 9 x 30 = 270

270 + 90 = 360

270 + 360 = 630

270/630 = 3/7

a) It was 3/7.


3 u --> 14 x 30 = 420

7 u --> 7/3 x 420 = 980 pupils

b) There wer 980 pupils.

No comments:

Post a Comment