This blog is managed by Song Hock Chye, author of Improve Your Thinking Skills in Maths (P1-P3 series), which is published and distributed by EPH.

Sunday, April 24, 2011

ACS Primary 2010 SA1 Math Paper 2 Q16

Mr Wu had some badges and decided to give them to his two sons, Sean and Matthew. Mr Wu gave 1/3 of the badges and 8 more badges to Sean. He then gave 3/4 of the remainder to Matthew but took back 2 badges. Mr Wu was left with 26 badges. How many badges did Mr Wu have at first?

Solution


Assume all badges --> 1 unit


Mr Wu was left with,

----- 1/4 of Remainder + 2

----- 1/4 x (2/3 unit - 8) + 2

= (1/6 unit - 2) + 2

= 1/6 unit - 2 + 2

= 1/6 unit

1/6 unit --> 26 badges

1 unit ----- 26 divided by 1/6
= 26 x 6
= 156

Answer: 156 badges

No comments: