Step-by-step explanation:
sum of the arithmetic sequence
a1 = 8
a2 = a1 + 8 = 8+8 = 16
...
an = 8×n
the sum of the first n elements of such a series is
n/2 × (2×a1 + (n - 1)×d]
with d being the difference between 2 consecutive elements (= the added constant).
so,
s30 = 30/2 × (2×8 + 29×8) = 15×(31×8) = 3720
Interest = Pin = principal * interest rate * number of years
Let interest rate be i, then
600*i*2+150*i*4=90
1200i+600i = 90
i=90/(1200+600)=90/1800=1/20=0.05 or 5%
150+3p
p=30
150+3(30)
150+90
240
When p=30 in 150+3p, the final value is 240.
14$ i think and good luck on ur test
