John's Mathematics exam mark this year is increased by 5% to 84. Find his Mathematics exam mark last year.

80%

Step-by-step explanation:

Let's call the past exam mark m,

m*105%=84

m*105/100=84

m=84/(105/100)

m=80

Hope this helps!

80

Step-by-step explanation:

new value = 84

old value = n

can use percent change formula:  (new value - old value) / old value = 5/100

=

cross-multiply (you can simplify 5/100 to be 1/20 first):  20(84 - n) = n

1680 - 20n = n

1680 = 21n

n = 80

yes

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step-by-step explanation:

3/6 chance

step-by-step explanation:

half of the nubers are odd numbers (1,3,5) which in that case if you would be told to simplify it would be 1/2