emaths qn

Maith SG

H=4/5(220-n)

make n the subject of this formula.

H= 176 - 4/5n

H-176 = -4/5n

H - 176/- 4/5 = n

correct? i dont have answer key so cannot check

deteq SG

think its correct. u can change the fraction to - 5(H-76)/4 i think.

iamapebble SG

H = 4/5(220-n)
H = 176 - 4/5n
4/5n = 176 - H
n = (176 - H) / (4/5)
n = (176 - H)(5/4)
n = 220 - (5/4)H

I think you got the answer but remember your brackets are important. :)

eagle SG

Maith, got technique to check one. And very quick.

Sub in values. For example,

H=4/5(220-n)
Sub n = 10,

H = 0.8 * 210 = 168

Then see iamapebble's answer
n = 220 - (5/4)H

Sub H = 168,
n = 220 - 210
n = 10

Since you get back n = 10, it means it is correct.

There are many such short techniques and strategies to do quick check for exams. Which is why I named my tuition as strategic tuition.... I like to focus on such quick check methods :D