D=number of dimes
q=number of quarters
let's count everything in cents
dimes are worth 10 cents
quarters are worth 25 cents
10d+25q=700
divide both sides by 5
2d+5q=140
he has 7 more quarters than dimes
q=7+d
subsitute 7+d for q in other equation
2d+5q=140
2d+5(7+d)=140
2d+35+5d=140
7d+35=140
minus 35 both sides
7d=105
divide both sides by 7
d=15
sub back
q=7+d
q=7+15
q=22
22 quarters and 15 dimes
1 km = 1000 m
So
x km = 3,400 m
that means 3.4 km would be equal to 3,400 m
your final answer is
Answer:
approximately 27 grams
Work Shown:
Half life formula
y = A*(0.5)^(x/H)
where,
A = starting amount = 30 grams
H = half life period = 90 years
x = number of years that pass by = 12
y = amount left over after x years
Let's plug the values for x, A and H into the formula to find y
y = A*(0.5)^(x/H)
y = 30*(0.5)^(12/90)
y = 27.3516746567466
y = 27 .... rounding to the nearest whole number
The question is not defined very well so if u would repeat it
The rule is exponential function.
