Daily Mail Mindbender Question 1 Friday 4Th April 2014

[ramblingrose]

Julie baked three fewer cupcakes than Steph, who made three times as many as Richard, who baked 15% as many as Jess. If they averaged 30 cupcakes each, how many did Steph bake?

The answer is 27 cupcakes. Can someone tell me out to arrive at this answer?

[sandyRoe]

jess 60
steph 27
eichard 9
julie 24

[sandyRoe]

I think I've worked this out but can't explain how. There may be a maths wizard along shortly.

[factor-fiction]

Total has to be 120 (based on average- assuming that's the mean- is 30).
Can then do it by algebra or by trial and improvement

[footy_le_bordel]

Convert terms for Steph

So:
Julie = S-3
Richard = S/3
Jess = S/3*20/3 = 20s/9

S = 120 - (S-3 + S/3 + 20s/9)
S = 123 - (S + S/3 + 20/9)

conver all fractions into 9ths

S = 123 - (9s + 3s/9 + 20/9)
S = 123 - (32s/9)

add 32s/9 to both sides

S + 32s/9 = 123

41s/9 = 123

41s = 123*9
41s = 1107

Divide both sides by 41 =

S = 27.

[footy_le_bordel]

I've written 20/9 a couple of times above when it should read 20s/9. Can't see an edit button so can't correct.