Question

the price of a delta airline ticket from los angeles to boston increased to $400. This is a 15% increase. what was the old fare?

Answer 1

100-15=?

Answer 2

85/100=0.85?

Answer 3

Now
0.85*400=?

Answer 4

when using percentages
to increase a number by 15 percent to equal 400
you have
\[\frac{ 15 \times x }{ 100 }+ x=400\]

Answer 5

rearrange to solve for x

Answer 6

where x is the starting price, 15/100 is 15% of the original number and 400 is the price it currently is

you could also do it another way

knowing it was increased by 15% then you know that 1 is 100% so 1+0.15 is 115% meaning x+15% of x

so 1.15x=400

solve for x

Answer 7

hope that makes it clearer for you :) btw Shamim is wrong, as it would only reduce your current number by 15%, it wouldn't give you the original number that was increased by 15%

Answer 8

@u009574

Answer 9

please tell me if you need help still or something explained