The easiest way is to use (& to memorize) the sum formula for a AP:
Sum = 1st term added to the last term & multiplied by half the number of terms
S = (a+l)n/2
S = (5 + 53)(7/2) = 203
No there totally differnt
Answer:
<h2><em>The percent decrease is approximately 40%. </em></h2>
Step-by-step explanation:
Step one:
given data
initial count of fish= 850
final count of fish= 500
Required
% decrease
Step two:
% decrease= final-initial/initial*100
substitute
% decrease= 850-500/850*100
% decrease=350/850*100
% decrease= 0.41*100
% decrease= 40.1%
<em>The percent decrease is approximately 40%. </em>
250 and - 1250
This is a geometric sequence with common ratio r = - 5
multiply each term by - 5 to obtain the next term
- 50 × - 5 = 250
250 × - 5 = - 1250
the sequence is - 2, 10, - 50, 250, - 1250

so.. as you can see, we use the decimal notation for the percentages... 65% is just 65/100 and 50% is just 50/100 and so on
so.. whatever the salted amounts are, we know they'll add up to (x+175)(0.50)
thus (0.30x) + (175)(0.65) = (x+175)(0.50)
solve for "x"