Question

There are seven pairs of black shoes and five pairs of white shoes. They all are put into a box and shoes are drawn one at a time. To ensure that at least one pair of black shoes are taken out, what is the number of shoes required to be drawn out? (

Answer 1

pair of black shoes=7

pair of white shoes=5

they all out together into a box so,

=7+5

=12

one pair of black shoes are taken out

therefore ,

=12-1

= 11pairs

hence ,11 pair of shoes required to be drawn out