Manori’s bag has 10cent and 20cent coins. She has 202 coins with a total value of $31.90. How many 20cent coins does manori have?

a = 85 10cent coins

b = 117 20cent coins

a = 10c coins

b = 20c coins

$31.90 = c3190

a + b = 202 => a = 202 - b

10a + 20b = 3190

10(202 - b) + 20b = 3190

2020 - 10b + 20b = 3190

10b = 3190 - 2020

10b = 1170

b = 117 (20cent coins)

a = 202 - 117

= 85 (10cent coins)

sinn is the total amount of students now and m were the students before, you subtract them both (n-m) and divide that by m. then, since to get a percentage from a fraction you have to multiply by 100, your answer should look like this: n-m/m*100

step-by-step explanation: