this just wants us to calculate 4/5-1/3
make common denom
4/5 times 3/3=12/15
1/3 times 5/5=5/15
4/5-1/3=12/15-5/15=(12-5)/15=7/15
7/15lb is left
Tripiling time is

t=time elapsed
r=tripling time
P=initial amount
so

when time is measured in minutes
if measured in hours then

or
Here we are given the three sides of the triangle.
So we have Heron's formula to find its area.
Heron's formula is given by :

where A, B and C are sides of triangle and S is semi perimeter which is given by,

plugging values of A, B and C to find S

S=13.5
Now plugging values of A, B , C and S in Heron's formula

A=26.14 mm²
Answer: Area of triangle is 26.14 mm².
Answer:
the area after 6 years is 3,473 km^2
Step-by-step explanation:
The computation of the area after 6 years is as follows:
= Area × (1 - decreased percentage)^number of years
= 4,800 km^2 × (1 - 5.25%)^6
= 4,800 km^2 × 0.9475^6
= 3,473 km^2
Hence, the area after 6 years is 3,473 km^2