2a + 6b = 24, 3a + b = 20
a + 3b = 12, a = 12 - 3b
3(12-3b) + b = 20
36-9b + b = 20
36-8b = 20
8b = 16
b = 2
2a + 12 = 24
2a = 12
a = 6
AC
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(b) In 2013, the price for each unit of electricity was 13.5 cents. Over the next 3 years, this price increased exponentially at a rate of 8% per year. Calculate the price for each unit of electricity after 3 years