Answer this maths questions plizz

Hey please try to answer all the questions below!! these are my revisional questions for my exams so please help me out!! Tomorrow is my exam!! thank you!!
a) 20% of $30
b) increase $200 by 10%
c) decrease $100 by 20%
d) $2 of $10
e) $80 of $175
f) divide $200 to the ratio 2:3
g) divide 80 coconuts in the ratio 1:2
h) increase $40 in the ratio 2:5
i) decrease 45 litres in the ratio 4:1
j) convert 6 hours to minutes
k) convert 3 km/hr to m/s
l) in one exam a student scored 40%. what was the mark of the student if the paper was out of 70

a) 20% of $30 = 0.20*30 = $6
b) increase $200 by 10% = $200+0.10*200 = $220
c) decrease $100 by 20% = 100-100*0.20 = $80
d) $2 of $10, I’m assuming you’re asking for percentage, = (2/10)*100% = 20%
e) $80 of $175 = similar to d), (80/175)*100% = 45.714% = 46%
f) divide $200 to the ratio 2:3 = (200*2)/3= 400/3 = $133.33
g) divide 80 coconuts in the ratio 1:2 = (80*1)/2 = 40 coconuts.
h) increase $40 in the ratio 2:5 = (40*2)/5]= $16
i) decrease 45 litres in the ratio 4:1 = (45*4)/1=180 litres.

j) convert 6 hours to minutes
1hour = 60 minutes
6 hours =?
Use cross multiplication
(6*60)/1 = 360 minutes.

k) convert 3 km/hr to m/s
3 km = 3000 meters
1 hour = 3600 seconds
Therefore,
3km/hr = 3000m/3600s =5m/6s = 0.833 m/s

l) in one exam a student scored 40%. what was the mark of the student if the paper was out of 70
= 0.40*70 = 28
The student received 28/70 which is 40%.

I'll answer some. What are revisional? You mean review?

a) 20% of $30 ............ 20% MEANS .2 so .2*30= $6 Do not foreget the label.
Prepare a well labeled worksheet.

b) increase $200 by 10% ahain it is .1*200= $20. Easy === Right.
c) decrease $100 by 20% A trick. 1-.2=.8 so .8*100= $80
d) $2 of $10 THIS DOES NOT MAKE SENSE