
By: veronica2566 (offline) Thursday, October 06 2011 @ 07:39 PM CDT (Read 2326 times)



veronica2566 
Appreciate if anyone can help :
1) Mr Yusof had a total of 328 blue and green pens in his bookshop. He sold 1/5 of his blue pens and bought another 47 green pens. After that, the number of green pens he had was 5/8 the number of blue pens. How many more blue pens than green pens did Mr Yusof have at first?
2) Mr Raziq spent a total of $63.80 on some badges and bookmarks. The number of badges he bought was twice the number of bookmarks. He paid $2.20 more for all the badges. If each bookmark cost $1.30 more than a badge, how many bookmarks did he buy?
3) A class of 42 pupils borrowed an average of 5 books, There are twice as many boys as girls in the class. The average number of books borrowed by the boys was 4. What was the average number of books borrowed by the girls?
4) Mr Tan placed some poles at 0.5m apart equally around his circular garden. The 5th pole as facing directly opposite the 14th pole. What was the perimater of the garden?
Thanks!

Junior
Registered: 06/23/10 Posts: 24





By: RachelAng (offline) Thursday, October 06 2011 @ 10:57 PM CDT



RachelAng 
3) A class of 42 pupils borrowed an average of 5 books, There are twice as many boys as girls in the class. The average number of books borrowed by the boys was 4. What was the average number of books borrowed by the girls?
3 units = 42 pupils
1 unit = 14 pupils
No. of girls in the class = 14.
No. of boys in the class = 28.
Total no. of books borrowed by class = 42 x 5 = 210.
No. of books borrowed by boys = 28 x 4 = 112.
No. of books borrowed by girls = 210  112 = 98
Average no. of books borrowed by girls = 98 / 14 = 7 (ANS)
4) Mr Tan placed some poles at 0.5m apart equally around his circular garden. The 5th pole as facing directly opposite the 14th pole. What was the perimater of the garden?
Pole 5 matches with Pole 14. Draw out in a circle and you get total 18 poles.
Distance between each pole is 0.5m.
Total no. of gaps = 18.
So perimeter of garden = 18 x 0.5 = 9m

Newbie
Registered: 01/23/11 Posts: 4





By: GIM (offline) Friday, October 07 2011 @ 09:40 AM CDT



GIM 
1. Mr Yusof had a total of 328 blue and green pens in his bookshop. He sold 1/5 of his blue pens and bought another 47 green pens. After that, the number of green pens he had was 5/8 the number of blue pens. How many more blue pens than green pens did Mr Yusof have at first?
Total blue & green pens = 328
Blue sold :1/5
Blue left : 1  1/5 = 4/5 = 8/10
Total blue was 10 units
Remaining blue is 8 units
Bought 47 green pens
Now green pens is 5/8 of blue pens
Green becomes 5 units
5 units of green + 10 units of blue  328 + 47=375
15 units  375
1 unit 375 /15 = 25
Total blue 10u x 25 = 250 pens
Total green  328  250 = 78
Difference = 250  78 = 172 more blue pens

Regular Member
Registered: 11/07/10 Posts: 70





By: veronica2566 (offline) Saturday, October 08 2011 @ 12:24 AM CDT



veronica2566 

Junior
Registered: 06/23/10 Posts: 24





By: qmzhou87 (offline) Monday, October 10 2011 @ 03:57 AM CDT



qmzhou87 
2) Mr Raziq spent a total of $63.80 on some badges and bookmarks. The number of badges he bought was twice the number of bookmarks. He paid $2.20 more for all the badges. If each bookmark cost $1.30 more than a badge, how many bookmarks did he buy?
63.82.2=61.6
61.6/2=30.8
He spent $30.8 on bookmark and $33 on bdages
$33/2=$16.5 He use this amount of money to buy half number of total badges, which is the same number of bookmarks he bought
$30.8$16.5=$14.3
$14.3/1.3=11
He bought 11 bookmarks and 22 badges.
$33/22=$1.5 per bagde
$1.5+$1.3=$2.8 per bookmark, $2.8*11=$30.8

Newbie
Registered: 10/09/11 Posts: 2





By: DEVBALAJI (offline) Wednesday, October 19 2011 @ 11:44 AM CDT



DEVBALAJI 
I believe there is a mistake in gmzhou87's solution. The amount of money he spent on the bookmarks is not the same as the amount spent on half of the badges as each bookmark costs $1.30 more than a badge.
My solution is as following:
$63.80  ($2.20 x 3) = $57.20 (excessive $1.30s)
$57.20 / $1.30 = 44 bookmarks
Comments are welcome!

Newbie
Registered: 12/31/06 Posts: 4





By: nisalam (offline) Thursday, October 20 2011 @ 09:20 PM CDT



nisalam 
I tend to agree with gmzhou. He never said that the amount spent on half the badges was the same as that on the bookmarks, only that the $30.80 paid for the bookmarks got him the same number of bookmarks as $16.50 on badges. Hence the difference between these sums divided by the unit difference ($1.30) indicates how many bookmarks there were (and by doubling, the number of badges).

Junior
Registered: 04/29/10 Posts: 30



