Number-randon Questions

Question 1

Simplify 3^5/3^10 (indices question

Answer 1

3^5-^10 =^-5

Question 2

Write 140 as the product of its prime factors

Answer 2

140 = 2^2x5x7
/.   \
2.   70
      /. \
     2.  35
           /. \
          3.  6 
               / \
              2. 3

Question 3

Work out 3/4x2/3

Answer 3

3x2/4x3=6/12

Question 4

Derek, Erica and Fred share £108 in the ratio 3:4:2 calculate the amount of money Erica gets

Answer 4

4+3+2=9
108/9=12
12x4=48

Question 5

The ratio of boys to girls in a class is 5:3 if there are 9 girls in the class, how many boys are there?

Answer 5

5:3
x3|. |x3
15:9. =15

Question 6

Write 37451 correct to 1 sigfig

Answer 6

4000

Question 7

Given that 48.6x35=1701

Write down the value of 4.86x3.5

Answer 7

48.6x35=1701
/10
4.86x3.5=17.01

Question 8

Write 7.21x10^-3 as an ordinary number

Answer 8

0.00721

Question 9

(6x10^4)x(4x10^3)

Answer 9

60000x4000=240000000=2.4x10^8

Question 10

Loft insulation reduces annual heating costs by 20%
After he insulted his loft, curtleys annual heating cost was £520
Work out curtleys annual heating cost would of been if he had not insulated his loft

Answer 10

520x0.2=104

520+104=624

Question 11

Work out 45 out of 60 as a percentage

Answer 11

45/60 =3/4=0.75=75%

Question 12

A man weighs65kg
After completing a diet he now weighs 39kg
What is his percentage decrease in weight

Answer 12

65
39-
___
26=26/65=2/5=0.4=40%

Question 13

Jack invests £3000 for 2 years at 4% per annum compound interest
Work out the value of the investment at the end of the 2 years

Answer 13

3000x1.04^2= £3244.80

Question 14

Mario invests £2000 for 3 years
For the first 2 years he earns 5% compound interest
For the last year he earns 3% compound interest
Calculate the value of the investment at the end of 3 years

Answer 14

£2000x1.05^2=

£

Question 15

If x=3.2 to 1 d.p. And y to 1 d.p. Calculate the upper and lower bounds of xy

Answer 15

15.475

Question 16

A studen bought a pair of sunglasses in the USA he paid $35.50
In England an identical pair of sunglasses costs £26,99
The exchange rate us £1=$1.42
In which country were the sunglasses cheaper and by how much?

Answer 16

£1=$1.42
)x25
£26.99=$35.50
USA -£1.99

Question 17

Express the recurring decimal 0.04’ as a fraction

Answer 17

R=0.04
Rx10=0.44
Rx100=4.44

100. 4.44. 4
     -10. -0.44. ___
     ____. _____. 90
101. 4

Question 18

Write down the reciprocal of 8

Answer 18

8=8. =1
___. ___
1. 8

Question 19

Find the value of 64^-1/3

Answer 19

64^-1/3
___
3/64 =4