Ineed answer ! timed !

what is the formula to find the original amount

first thing you have to do is consider the unknown original amount as ‘x’.

next, consider the percent rate of increase or decrease

to find the increase or decrease, you must multiply the rate by the original amount ‘x’.

to find the final amount, add or subtract the increase or decrease to the original amount ‘x’ and equate this to given final amount.

solve the equation and find the original amount of ‘x’.

example:

step 1:

after a 25% increase, a couch was $750. find the original price

first asociate numbers with letters,   the original amount be = x

percent increase = 25%

step 2:

increase in price = 25% of x = 0.25 × x = 0.25x

final amount would be = original amount + increase = x + 0.25x = 1.25x

step 3:

final amount = $750 = 1.25x

solving for ‘x’:

x = 750/ 1.25 = $600

this, the original price was $600

hope this ! : )

hello,

b) 62.47% of the students are between 14 and 18 years old.

step-by-step explanation:

mean = 15 and standard deviation = 2

student between 14 to 18

formula used z-score

for age 14 , z score

using z-table , p(z> -0.5)=0.3085

for age 18 , z score

using z-table , p(z< 1.5)=0.9332

p(-0.5< z< 1.5)=0.9332-0.3085 = 0.6247

thus, 62.47% of the students are between 14 and 18 years old.

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step-by-step explanation: