i believe michael would be 36. hope this
x = michael age
y = brandon age
x = 4y
x = y + 27
put the system of linear equations into standard form
x - 4y = 0
x - y = 27
x = michael age = 36
y = brandon age = 9
the general formula for compound interest is
a = p(1 + r/n)^nt where p = initial amount, r = yearly rate ( as a fraction), t = number of years and n = number of times in the year that interest is added.
so for the given data:
amount after 1 year = 500 ( 1 + 0.05/365)^365
sweater is 32$ which was 30% added.
$32$ is 70% of the price.
so multiply it by 0.70
it used to be 22.4$