There are 64 students in a speech contest. Yesterday, Ā of them gave their speeches. Today, 7 of the remaining students gave their speeches. How many students still haven't given their speeches?
M

23

Step-by-step explanation:

Ā means the average

So it means the average of 64 gave their speech which should be 64/2 = 32

So 32 gave their speeches yesterday,

7 gave today

Total number that has given is

32 + 7 = 39

Therefore the number remaining are

62 - 39 = 23

x=-1/3

Step-by-step explanation:

12-(3x+13)=0

12-3x-13=0

-3x-1=0

-3x=1

x=-1/3