Answer:
−9
Step-by-step explanation:
A ratio of 5:7 means out of 12 books, 5 are in one category and 7 are in another. (The “category” isn’t specified in this problem.)
So here we’re STARTING with 36 books; we want to find a ratio that is equal to 5:7 and adds up to 36. Well 36 = 3(12), and so if we multiply each number in the ratio by 3 as well, we might get what we want. Doing that gives us 15:21, which adds up to 36 and is equal to 5:7. Boom, that’s the answer.
P.S. Here’s a question you can think about: why do ratios stay the same when you multiply each number by the same amount? (For example, why is 3:1 the same as 6:2?)
Step-by-step explanation:
∑k=150(3k+2)
First find a1 and a50 :
a1=3(1)+2=5a20=3(50)+2=152
Then find the sum:
Sk=k(a1 + ak)2S50=50(5 + 152)2=3925
Answer:
9 hours
Step-by-step explanation:
36 degrees total /4 degrees per hour = 9 hours
Answer:
P(t) = 12e^1.3863k
Step-by-step explanation:
The general exponential equation is represented as;
P(t) = P0e^kt
P(t) is the population of the mice after t years
k is the constant
P0 is the initial population of the mice
t is the time in months
If after one month there are 48 population, then;
P(1) = P0e^k(1)
48 = P0e^k ...... 1
Also if after 2 months there are "192" mice, then;
192 = P0e^2k.... 2
Divide equation 2 by 1;
192/48 = P0e^2k/P0e^k
4 = e^2k-k
4 = e^k
Apply ln to both sides
ln4 = lne^k
k = ln4
k = 1.3863
Substitute e^k into equation 1 to get P0
From 1, 48 = P0e^k
48 = 4P0
P0 = 48/4
P0 = 12
Get the required equation by substituting k = 1.3863 and P0 = 12 into equation 1, we have;
P(t) = 12e^1.3863k
This gives the equation representing the scenario