Tuesday 14 August 2012

Challenging Math problem sums

Repost with permission from Miss Alexis Tung's class blog.

Dear 4F pupils,

Please try out the questions and check your answers against the answer key found at the end of the blog post. Questions 1-5 for Day 1 (Thursday 16 August) and questions 6-16 for Day 2 (Friday 17 August). If you are unable to solve the question, then you may refer to the video link for explanation.

Once you are done with these 16 sums, please proceed to LMS learning portal. There are some English, Math and Sci lessons set for you as extra revision. This is new, I've not announced to you just now in class. Do not worry about not being able to complete the LMS homework. You have up till Thursday to complete everything in LMS.


1) The number of turtles is 1/6 the number of dogs. The total number of cows and dogs is 136. The total number of cows and turtles is 76. How many cows are there?
Solution

2) Two different numbers were written on the board. Paul added them while Mike subtracted the small number from the big one. The difference in their answers was 76. If the big number was 56 more than the small number, what is the bigger number?
Solution

3) Fred has $12 more than Dave. If Dave gives $3 to Fred, Dave will have 3/4 of Fred's money. How much do they have altogether?
Solution

4) Ben has 3 times as much savings as Dave. Aaron has $50 less than Dave. They have a total of $1650. How much must Ben give to Aaron so that both will have the same amount?
Solution

5) If Jack gave $400 to Fred, they will have the same amount of money. However, Jack decided to give more to Fred. In the end, Fred had $570 more than Jack. What is the total amount that Jack give Fred?
Solution

6) 9/11 of the fruits are oranges, the rest are apples. How many apples are there if there are 2871 oranges?
Solution

7) Ethan and Dave had the same amount of money. After Ethan gave $31 to Dave, Dave had 3 times as much money as Ethan. How much did Dave have in the end?
Solution

8) A packet of guavas has a mass of 1.4kg. A packet of apples has a mass of 0.6kg. 5 more packets of guavas than apples were sold. The total mass of both fruits sold is 11kg. How many packets of guavas are sold?
Solution


9) How many hundreds must be added to 6000 to make 24 000?

10) 34 is added to a mystery number. The result is multiplied by 3. After that 23 is subtracted. The final value is 292. What is the mystery number at the beginning?

11) What is the sum of all the common factors of 10 and 18?

12) Bell A rings every 8 minutes. Bell B rings every 2 minutes. If both bells ring together at 8.46 p.m, when will they ring together again?

13) A pack of 4 pens costs $19. A pack of 8 files cost $14. Wayne wants to buy an equal number of pens and files. What is the least amount that he must pay?

14) There are 4 times as many girls as boys at a fair. How many children are there altogether if there are 3256 girls?

15) A table and 2 chairs cost $432. The table costs 4 times as much as a chiar. Find the cost of a table.

16) 9 ties and 6 shirts cost $534. A tie cost $6 more than a short. Find the cost of a tie.


ANSWERS
1) 64 COWS
2) BIGGER NUMBER: 94,  SMALLER NUMBER: 38
3) TOTAL: 126, FRED: 69, DAVE: 57
4) $365
5) $685
6) 638 apples
7) $93
8) 7 packets
9) 180 hundreds
10) 71
11) 3
12) 8.54 p.m.
13) $52
14) 4070 children
15) $288
16) $38