-3x4.5=13.5. 4.5x0.5=2.25
-13.50
+2.25
_____
15.75 pints
The answer is D, 10. 4 years ago she was 6, so William must have been 1 (1/6 of 6). In 6 years time she will be 16 (10+[4+6 years]).
<u>Given</u><u> </u><u>that</u><u>:</u><u>-</u>
→ 1 sandwich = 2 slices of bread.
→ 1 hiker = 1 sandwich.
→ Then we have to find number of bread slices for n hikers .
→ Number of bread slices for 1 hiker = 2
→ Number of bread slices for 2 hikers = 2 × 2
→ For 3 hikers = 3 × 2
So in similar way
→ Number of bread slices for n hikers = 2×n → 2n
So <u>2</u><u>n</u><u> </u> is the answer.
Answer:
(A) 
with 
.
(B) 
with
(C) 
with 
(D) 
with ,
Step-by-step explanation
(A) We can see this as separation of variables or just a linear ODE of first grade, then 
. With this answer we see that the set of solutions of the ODE form a vector space over, where vectors are of the form 
with 
real.
(B) Proceeding and the previous item, we obtain 
. Which is not a vector space with the usual operations (this is because 
), in other words, if you sum two solutions you don't obtain a solution.
(C) This is a linear ODE of second grade, then if we set 
and we obtain the characteristic equation 
and then the general solution is with , and as in the first items the set of solutions form a vector space.
(D) Using C, let be 
we obtain that it must satisfies 
and then the general solution is with , and as in (B) the set of solutions does not form a vector space (same reason! as in (B)).
