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.
Answer:
504 * 0.12 = 60.48
Step-by-step explanation:
math
The speed of water current is 1.8 mph
Step-by-step explanation:
1.
The speed of steamer in still water IS 18 mph
Let the speed of current be x mph
When traveling downstream, the distance between the two ports is covered in 3 hours.The steamer is helped by the current , so the speed will be ;
18 +x mph
The distance travelled downstream will be 3(18+x) miles.
2.
Travelling upstream, the time used by the steamer is 3 hours and 40 minutes, which is equivalent to 3 2/3 hrs. Traveling upstream , the current will hinder the streamer , thus the speed will be (18-x) mph.
Distance travelled upstream will be 3 2/3 * (18-x) miles
Equate the two equations for distance to get value of x
3(18+x) = 3 2/3 (18-x)
3(18+x)= 11/3 (18-x)
9(18+x)=11(18-x)
162 +9x =198-11x
9x+11x =198-162
20x=36
x=36/20 = 1.8 mph
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Keywords : speed
#LearnwithBrainly
Given :
Liam has a bag of b beads.
He gives 20 beads to his sister.
He then makes 4 necklaces with the same of beads on each necklace using all of the remaining beads.
To Find :
Write an expression that represents the number of beads on each necklace.
Solution :
Number of necklace remains after giving 20 beads to his sister is ( b - 20 ).
Number of beads on each necklace using all of the remaining beads is :
Hence, this is the required solution.
Answer:
factors are <em>(x-1),(x+2),(x+4),(x+3)</em>