Author: George

Last week’s answer: 13. You should memorise the prime numbers up to 20, and remember that 1 is not prime!

This week’s problem: The conversion rate for pounds to euros is £1 to €1.10. If Sofia wants to convert £50 into euros, how many euros will she get?

The answer will be in next week’s weekly problem.

After a long hiatus, the weekly problems are back!

Last week’s answer: 15%. If we write 30/200 as a fraction then simplify it down to 15/100, it can then be converted to a percentage by just taking the numerator (as per cent means over 100).

This week’s problem: What is the 6th prime number?

The answer will be in next week’s weekly problem.

Last week’s answer: The sugar will now weigh 500g. 25% of 400g is 100g, so 25% extra is 400g plus an additional 100g = 500g.

This week’s problem: What percentage of £2 is 30p?

The answer will be in next week’s weekly problem.

Last week’s answer: 253 + 747 = 1000. The original question (2_3 + _4_ = 1000) is exactly the same as 243 + ___ = 1000, and becomes a simple subtraction problem. 1000 – 243 = 757, so those are the digits. Simply substitute them in to get the answer.

This week’s problem: A supermarket says that the sugar it now sells has 25% extra free. How much will it weigh if the sugar used to have 400g in the tub?

The answer will be in next week’s weekly problem.

Last week’s answer: 17:30 or 5:30 pm. The duration of the flight is 14 hours, so the time of arrival in GMT would be 8:30 + 14 hours = 22:30. Then you would take off 5 hours for the difference to get 17:30.

This week’s problem: Write the missing digits to make the sum correct.

2_3 + _4_ = 1000

The answer will be in next week’s weekly problem.

 

Last week’s answer: 12.5%. This is a simple fraction-to-percentage conversion, which you would just have to memorise.

This week’s problem: Lima, Peru is five hours behind GMT. If a plane leaves London at 08:30 GMT, write the local time it lands in Lima if the flight takes fourteen hours.

The answer will be in next week’s weekly problem.

Last week’s answer: 56p. The mean is a type of average where you sum all of the values and divide them by the number of values. In this case, the total is 10p + 20p + 50p + (2 x 100p) = 280p. Divide this by the number of values (5) to get the mean of 56p.

This week’s problem: 1/8th of Henry’s corn crops have died as a result of bugs in his corn field. What is this as a percentage of his total corn crops?

The answer will be in next week’s weekly problem.

Last week’s answer: She will need 450g of beef, and 50g of garlic. 1/2 of 900g is 450g, which is how much beef she needs. She also needs 1/3 of 900g = 300g of potatoes and 1/9 of 900g = 100g of carrots. Therefore she needs 900g – 450g – 300g – 100g = 50g of garlic.

This week’s problem: There are five coins in a bag – one 10p, one 20p, one 50p and two £1 coins. What is the mean of these amounts?

The answer will be in next week’s weekly problem.

Last week’s answer: 61p, 62p and 65p. 61p can be made from 50p, 10p and 1p. 62p can be made from 50p, 10p and 2p. 65p can be made from 50p, 10p and 5p. Neither of the other two can be made using just three coins.

This week’s problem: Louise is making beef stew.

1/3 of the stew is made from potatoes.
1/2 is made from beef.
1/9 is made from carrots.
The rest is made from garlic.
If she makes 900g of soup in total, how much beef does she need? And how much garlic?

The answer will be in next week’s weekly problem.

 

Last week’s answer: 32. The sequence is a series of doubling: 1 x 2 = 2, 2 x 2 = 4, 4 x 2 = 8 etc. The next number is obtained by doubling the last term in the sequence, and so is 2 x 16 = 32.

This week’s problem: Identify which of the amounts below can be made using three UK coins.
61p                    62p                    63p                    64p                    65p

The answer will be in next week’s weekly problem.