Answer:
Krista put 0.40 in the first equation meant for the number of stamps.
Step-by-step explanation:
Krista's equation
0.40x+y=45
x+0.55y=18.75
The system of Equation should have been
x + y = 45 (1)
0.40x + 0.55y = 18.75 (2)
From (1)
x=45-y
Substitute x=45-y into (2)
0.40(45 - y) + 0.55y = 18.75
18 - 0.40y + 0.55y = 18.75
Collect like terms and you now have
0.55y - 0.40y = 18.75 - 18
0.15y = 0.75
Divide both sides of the equation by 0.15
y = 5
Substitute y=5 into (1)
x + y = 45
x+5=45
x=45-5
x=40
This shows that the stamps that cost 0.40 cents were 40 while those that cost 0.55 cents were 5 in number.
Krista's error:
Krista put 0.40 in the first equation meant for the number of stamps.
It took Andre and Lin 1.5 hours for them to meet.
Speed is the ratio of distance travelled to total time taken. Speed is given by:
Speed = distance/time
Let d₁ represent the distance covered by Andre at time t and d₂ represent the distance covered by Lin at time t.
Hence:
5 = d₁/t
d₁ = 5t
3 = d₂/t
d₂ = 3t
Andre and Lin are 12 miles apart, hence:
d₁ + d₂ = 12
5t + 3t = 12
8t = 12
t = 1.5 hours
It took Andre and Lin 1.5 hours for them to meet.
Find out more on speed at: brainly.com/question/3004254
Answer:
4 weeks
Step-by-step explanation:
Company A charges $40 per week and a one time fee of $25
Company B charges $35 per week and a one time fee of $45
Therefore the number of weeks required for both companies to arrive at the same cost can be calculated as follows
Company A = 45 + 35×4
= 45 + 140
= 185
Company B = 25 + 40×4
= 25 + 160
= 185
Hence it will cost both companies 4 weeks
Answer:
j=k+3 (j=jason k+kieth)
Step-by-step explanation:
he did thrhee more so it will be adding 3 to k