Answer: 12
Step-by-step explanation:
Answer:
2097150
Step-by-step explanation:
<u>GIVEN :-</u>
- First term of G.P. = 6
- Forth term of G.P. = 384
<u>TO FIND :-</u>
- Sum of first 10 terms of the G.P.
<u>CONCEPT TO BE USED IN THIS QUESTION :-</u>
<em>Geometric Progression :-</em>
- It's a sequence in which the successive terms have same ratio.
- General form of a G.P. ⇒ a , ar , ar² , ar³ , ....... [where a = first term ; r = common ratio between successive terms]
- Sum of 'n' terms of a G.P. ⇒
.
<em>[NOTE :- </em>
can also be the<em> formula for "Sum of n terms of G.P." because if you put 'r' there (assuming r > 0) you'll get negative value in both the numerator & denominator from which the negative sign will get cancelled from the numerator & denominator. </em><em>YOU'LL BE GETTING THE SAME VALUE FROM BOTH THE FORMULAES.</em><em>]</em>
<u>SOLUTION :-</u>
Let the first term of the G.P. given in the question be 'a' and the common ratio between successive terms be 'r'.
⇒ a = 6
It's given that <u>forth term</u> is 384. So from "General form of G.P." , it can be stated that :-
![=> ar^3 = 384](https://tex.z-dn.net/?f=%3D%3E%20ar%5E3%20%3D%20384)
![=> 6r^3 = 384](https://tex.z-dn.net/?f=%3D%3E%206r%5E3%20%3D%20384)
Divide both the sides by 6.
![=> \frac{6r^3}{6} = \frac{384}{6}](https://tex.z-dn.net/?f=%3D%3E%20%5Cfrac%7B6r%5E3%7D%7B6%7D%20%3D%20%5Cfrac%7B384%7D%7B6%7D)
![=> r^3 = 64](https://tex.z-dn.net/?f=%3D%3E%20r%5E3%20%3D%2064)
![=> r = \sqrt[3]{64} = 4](https://tex.z-dn.net/?f=%3D%3E%20r%20%3D%20%5Csqrt%5B3%5D%7B64%7D%20%3D%204)
Sum of first 10 terms ![= \frac{6(4^{10}-1)}{4 - 1}](https://tex.z-dn.net/?f=%3D%20%5Cfrac%7B6%284%5E%7B10%7D-1%29%7D%7B4%20-%201%7D)
![= \frac{6(1048576 - 1)}{3}](https://tex.z-dn.net/?f=%3D%20%5Cfrac%7B6%281048576%20-%201%29%7D%7B3%7D)
![= 2 \times 1048575](https://tex.z-dn.net/?f=%3D%202%20%5Ctimes%201048575)
![= 2097150](https://tex.z-dn.net/?f=%3D%202097150)
The shop makes 25% profit if the cost price per dress is R280.
1 cup equals 8 fluids oz
1/2 equals 4 fluids oz
so 28 fluids oz