There is a bag with only red marbles and blue marbles. The probability of randomly choosing a red marble is
11
12
.
There are 72 marbles in total in the bag and each is equally likely to be chosen.
Work out how many red marbles there must be

12

Step-by-step explanation:

because there is 72 in it and probability of of it being 12 out of 72 is higher than 11

step-by-step :

answer: the angel abc is 30°,and the abc is a triangle where the angel bac is 90°

so ac is the half of 24=12ft,and from the pythagorean theorem we find ba

ba=√bc^2-ac^2=√576-144=√432=12√3ft

so bac is 12+12√3=12(1+√3)ft