Step-by-step explanation:

Answer:
J-o+e m=a+m-a
Step-by-step explanation:D+e_e_z n-u+t-s
Answer:
B and D
Step-by-step explanation:
Answer:
D = L/k
Step-by-step explanation:
Since A represents the amount of litter present in grams per square meter as a function of time in years, the net rate of litter present is
dA/dt = in flow - out flow
Since litter falls at a constant rate of L grams per square meter per year, in flow = L
Since litter decays at a constant proportional rate of k per year, the total amount of litter decay per square meter per year is A × k = Ak = out flow
So,
dA/dt = in flow - out flow
dA/dt = L - Ak
Separating the variables, we have
dA/(L - Ak) = dt
Integrating, we have
∫-kdA/-k(L - Ak) = ∫dt
1/k∫-kdA/(L - Ak) = ∫dt
1/k㏑(L - Ak) = t + C
㏑(L - Ak) = kt + kC
㏑(L - Ak) = kt + C' (C' = kC)
taking exponents of both sides, we have

When t = 0, A(0) = 0 (since the forest floor is initially clear)


So, D = R - A =

when t = 0(at initial time), the initial value of D =

Step-by-step explanation:
a)
we have 400 people. that is 10/10 of the whole group.
7/10 of the whole group drink tea. that is
400 × 7/10 = 40 × 7 = 280
that leaves 3/10 of the whole group not drinking tea
400 × 3/10 = 40 × 3 = 120
from the 280 tea drinkers 20% drink at lay e cups of tea each day. that is
280 × 20/100 = 28 × 2 = 56
because 20 out of 100 is the meaning of 20%.
and the remaining 80% of the tea drinkers drink less then 3 cups each day.
280 × 80/100 = 28 × 8 = 224
b)
out of the 400 people 56 drink at least 3 cups of tea each day. that is
56/400 = 7/50