Asked by anonymous

1) Write 0.78787878787878.... (recurring) as a percentage.

2) The price of petrol increased by 10%.
Six months later it increases again by 10%
There was no other price changes.

What was the total percentage increase in the price of the petrol.
Answered by Reiny
let x = .787878...
multiply by 100, (there are 2 digits repeating, if there had been 3 digits repeating, I would have multiplied by 1000)
100 x = 78.787878..
subtract them: notice the decimals line up nicely to get
99x = 78.0000...
x = 78/99 = 26/33

(check with your calculator)

What is (1.1)(1.1) ??
Answered by anonymous
understood question 1 but i don't really understand what you said for question 2. Please can you explain?
Answered by Reiny
To increase something by 10% , multiply by (1 + 10/100)
= 1 + .1
= 1.1
so you are doing this a second time ----> (1.1)(1.1) = 1.21 = 1 + .21 = 1 + 21/100
so the net increase is 21%

check:
suppose an article costs $250 , increase it by 10% -----> 1.1(250) = $275.00
increase it again by 10$ ----> 1.1(275) = $ 302.50

single increase of 21% ----> 1.21(250) = $302.50
Answered by Elisha
At school yo increase something we would multiply it by 10 so I have no idea what you are talking about sorry please could you show it in an easier way.
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