Combinations

Sarah C · Post by **Sarah C** » Wed Nov 01, 2006 6:54 pm

Please could someone help a mum with a complete mental block?

You have 5 ties, 4 shirts and 3 shorts. How many combinations? I know I should know this and in the dim and distant past I must have done this type of question but HELP!!

SJ · Post by SJ » Wed Nov 01, 2006 8:59 pm

5x4x3=60?

Sarah C · Post by **Sarah C** » Wed Nov 01, 2006 9:10 pm

Oh dear! Was it really as easy as that?

Many thanks for your help.

explanation · Post by **explanation** » Thu Nov 02, 2006 2:40 pm

Try to visualise the shirts/ties/shorts to make sense of the formula

e.g each of the 5 ties can go with shirt 1

tie 1- shirt 1
tie 2 - shirt 1
tie 3 - shirt 1
tie 4 - shirt 1
tie 5 -shirt 1
Similarly each tie can go with shirt 2, shirt 3 and shirt 4.

So that will give you 5+5+5+5 (or 4x5 = 20) different tie-shirt combinations.

Then each of the three pairs of shorts can go with each of the 20 shirt/tie combinations

so shorts 1 with 20 shirt tie combinations, plus
shorts 2 with 20 shirt-tie combinations, plus
shorts 3 with 20 shirt-tie combinations

=3x20 cobinations

so answer is no of tiesx no of shirtsx no of shorts

Hope that helps.

Failing that, raid your partner's or son's wardrobe and lay them out!!