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PLEASE HELP ME ASAP! BRAINLIEST TO THE CORRECT ANSWERS.
1) In a sale, all prices are reduced by 30%. If the sale price of a washing machine is $245, what was the original price??

2) Prices in a shop are all increased by 5%. A shirt now costs $63. What was the original price??

3) A bank account gives 3% compound interest on savings. Eric invests $500. How long will he have to invest it before he has over $1700 in the account???

Respuesta :

Answer:

1) $350, 2) $60, 3) approximately 41.4 compound periods.

Step-by-step explanation:

1) (Original price)*(100% - 30%) = 245, so that

Original Price = 245 / (70%) = 245 / .7 = $350

2) (Original Price) * (100% + 5%) = 63, so that

Original Price = 63 / 1.05 = $60

3) For N compound periods (second, minute, day, week, month, year, bi-year, et. al.), we have that

500 * (100% + 3%)^N = 1700, so that

1.03^N = 1700/500

N = ln(1700/500) / ln(1.03) = 41.4013877024 = approximately 41.4

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