Eric purchased three music CDs and a sweatshirt from a band's online store and received a 20% discount. He paid $100 for his pur
2 answers:
Answer:
Cost of sweetshirt = 50 and cost of CD = 25
Step-by-step explanation:
Eric purchased three musics CDS and a sweatshirt
Let cost of CDs =c and cost of a sweatshirt =s
When after discount, 100 he pays means total cost =
Hence we have
3c+s=125
Similarly when 120 is paid after 40% discount,
cost =
i.e.
Divide by 2
Solving the two equations
Cost of sweetshirt = 50 and cost of CD = 25
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Let's start by visualising this concept.
Number of grains on square:
1 2 4 8 16 ...
We can see that it starts to form a geometric sequence, with the common ratio being 2.
For the first question, we simply want the fifteenth term, so we just use the nth term geometric form:
Thus, there are 16, 384 grains on the fifteenth square.
The second question begs the same process, only this time, it's a summation. Using our sum to n terms of geometric sequence, we get:
Thus, there are 32, 767 total grains on the first 15 squares, and you should be able to work the rest from here.
Number of grains on square:
1 2 4 8 16 ...
We can see that it starts to form a geometric sequence, with the common ratio being 2.
For the first question, we simply want the fifteenth term, so we just use the nth term geometric form:
Thus, there are 16, 384 grains on the fifteenth square.
The second question begs the same process, only this time, it's a summation. Using our sum to n terms of geometric sequence, we get:
Thus, there are 32, 767 total grains on the first 15 squares, and you should be able to work the rest from here.