2 simple math probs: What is 20% of 80? and 2/5 of 90

Please tell me how you got it, i cant find my notes from high school.

In a group of 80 students, 20% are psychology majors. How many psychology majors are in this group?

A company reports that 2/5 of its employees are women. If there are 90 employees, how many are women?

20/100 = x/80 Set up a Proportion
100x = 1600 Cross multiply
x = 1600/100 Divide by 100
x=16 Psychology Majors

2/5 = 40%
40/100 = x/90
100x = 3600
x = 36 Employees are women

1).
In a group of 80 students, 20% are psychology majors.
How many psychology majors are in this group?
16 psychology majors are in this group.

2).
A company reports that 2/5 of its employees are women.
If there are 90 employees, how many are women?
The company has 36 women employees.

In a group of 80 students, 20% are psychology majors

its nothing but 80x 20/100
therefore 16 students are psychology majors

A company reports that 2/5 of its employees are women

its nothing but (2/5)x 90
therefore 36 women are there...........

u need to do a proportion. like x over 100. 20 over 80% so kinda like

x 20
---- = -----
100 80 and then u cross multiply or u can just use your calculator 80x.20


same thing for the other problem 90 x
-------- = --------- BUT im not sure the order of the numbers is right so yea
40% 100%

.2 times 80 is 16. 2/5 is 40 percent so .4 time 90 is 36. Just make the percent a decimal and multiply it by the number.

20 * 80 = 1600/100 = 16 Majors

2/5=0.4 = 40% so:
40 * 90 = 3600/100 = 36 women

.2x80=16

2/5=.4
.4*90=36

20% = .2 x 80 = 16

2/5 x 90

90 x 2 = 180/5 = 36