Help asap in a class of 30 students 20%have black hair 10%have blonde hair and 70%have brown hair calculate the numbers of students black hair blonde hair and brown hair​

Ijust need to see how to do this. so you don’t have to answer all of them just a step by step explanation of one.

Find the exact value of each of the following. in each case, show your work and explain the steps you take to find the value. (a) sin 17π/6 (b) tan 13π/4 (c) sec 11π/3

Prove the divisibility of the following numbers: 25^9 + 5^7 is divisible by 30.also, read as (25 to the power of 9) + (5 to the power of 7) is divisible by 30. blank x 30what is the blank? ( it should be expressed in exponent form)