
By: LimKopi (offline) Friday, July 20 2012 @ 04:30 AM CDT (Read 1916 times)



LimKopi 
1. 6 pupils took part in Maths competition. Their average score was 91. The max score each pupil could get was 100.
The 6 pupils had different scores and each score was a whole number. If one of the pupils scored 65 marks, what was
the minimum score the pupil in the third position could get?
2. A dog and a cat were having a chasing game with the dog chasing the cat.
Whenever the dog jumped once, it covered a distance of 1.8m.
Whenever the cat jumped once, it covered a distance of 1.1m.
The ratio of the number of times the dog jumped to the number of times the cat
jumped was 2 : 3. If the race started with the dog and the cat being 30 m apart,
how many meters must the dog jump before it could catch up with the cat?
3. A shopkeeper bought some mangoes to sell. On Monday, he sold them at
25% above the price he had paid and managed to sell 20% of the mangoes.
On Tuesday, he sold the mangoes at 13% less than the price he sold on Monday
and he managed to sell all the mangoes. He made a total of $ 900 from the sale
of all the mangoes in the 2 days. What was the price he had paid for the mango

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Registered: 09/20/10 Posts: 1





By: GIM (offline) Friday, July 20 2012 @ 10:20 AM CDT



GIM 
Q1 solution:
Total score = 6 x 91 = 546
Since 1 person scored 65 marks, then total of remainding 5 person = 546  65 = 481
List down the possibilities starting with 100 as 1st number, then deduct each number from 481 to get the 5th person's scores.
481100=381 ; 38199=282 ; 28298=184 ; 18497=87
10099989787 (the 3rd position is 98)
(1)(2)(3)(4)(5)
9998979691 (the 3rd position is 97)
(1)(2)(3)(4)(5)
9897969595 (not possible as the last 2 numbers are the same)
9796959499 (the 3rd position is 96)
(2)(3)(4)(5)(1)
96959493103 (not possible as the max is 100)
From the above, the minimum score for pupil in third position is 96.

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





By: jo sarah (offline) Monday, July 30 2012 @ 11:10 AM CDT



jo sarah 
3. A shopkeeper bought some mangoes to sell. On Monday, he sold them at
25% above the price he had paid and managed to sell 20% of the mangoes.
On Tuesday, he sold the mangoes at 13% less than the price he sold on Monday
and he managed to sell all the mangoes. He made a total of $ 900 from the sale
of all the mangoes in the 2 days. What was the price he had paid for the mangoes?
Let the price paid for one mango be $p
and no. of mangoes be n. Thus, he paid $np for all the mangoes.
Monday: at $1.25p, sold 0.2n mangoes
so, he collected $1.25p x 0.2n = $0.25np
Tuesday: at $0.87 x 1.25p, sold 0.8n mangoes
thus, he collected $0.87np
In total, he collected $(0.25np + 0.87np) = $1.12np
He made (i.e profit) $1.12np  $np = $900
therefore, 0.12np = 900
and so, np = 900 / 0.12 = $7500
He paid $7500 for the mangoes.

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Registered: 03/20/12 Posts: 111





By: GIM (offline) Friday, August 03 2012 @ 01:57 AM CDT



GIM 
Question 2
{? jumps}
{30m}

Dog___________cat____________meet
Start__________start___________together
____Unit___Dist____ Dist units
Dog21.8m2 x 1.8 = 3.6
Cat31.1m3 x 1.1 = 3.3
Difference : 3.6  3.3 = 0.3 units
0.3 unit > 30m
1 unit> 30m / 0.3m = 100
Dog>2 x 100 x 1.8m = 360 m
The dog needs to jump 360m to catch up with cat.
Check :
(2 x 100 x 1.8) = (3 x 100 x 1.1) + 30m
________360 = 360

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



