Maths question - can anyone help please?

[emkana]

Each boy danced with exactly four girls and each girl danced with exactly five boys at a party. If 45 students attended the party, how many boys were there?

[eatyourveg]

omg I got it right and I'm crap at maths!

I just did 4 x 5 =20 girls
45 people -20 girls = 25 boys

[emkana]

Thanks everyone

[fuzzpig]

I am stumped with this one. I'm normally good at putting word problems like this into equations but i wouldn't have a clue how to do this without trial and error.

[Quangle]

That's what I was thinking pourme. But patricia s way is good.

[pourmeanotherglass]

I think that is a badly written question, as there should be more information to ensure there is only one answer. It would work with any combination so long as there are at least 4 girls and 5 boys.

[Bumpinthenight]

4g
--- = 45 so 45 / 5 x 4 = 20 girls 45 - 20 girls = 25 boys
5b

[Quangle]

Ok so it could be different combinations of the same 4 girls. Otherwise there'd have to be 100 girls.

I am no help

[emkana]

Sorry cross posted! Is the * sign for multiply?

[Quangle]

Yikes I can't answer that. Is it supposed to be each boy dancing with four different sets of girls do you think? I can't work it out either way tbh.

[PatriciaHolm]

b4 = c5

b+c =45

so (b4)/5 = c

so b+ (b4)/5) = 45

so b + (b*(4/5)) = 45

4/5 is the same as 0.8

so 1.8 B=45

so Boys = 25, Girls 20.

[emkana]

Maybe, thank you, but I need the workings!

[springalong]

I loves maths puzzles but am stuck. I really should give up my teacher training for Maths at GCSE

[AgentProvocateur]

25?