How many different arrangements of 3 letters can be formed if the First letter must be W or K
2 answers:
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Answer:
Perimeter = 18.7 units
Area = 13.5 units²
Step-by-step explanation:
Perimeter of ADEC = AD + DE + EC + AC
Length of AD = 3 units
By applying Pythagoras theorem in ΔDBE,
DE² = DB² + BE²
DE² = 3² + 3²
DE = √18
DE = 4.24 units
Length of EC = 3 units
By applying Pythagoras theorem in ΔABC,
AC² = AB² + BC²
AC² = 6² + 6²
AC = √72
AC = 8.49 units
Perimeter of ADEC = 3 + 4.24 + 3 + 8.49
= 18.73 units
≈ 18.7 units
Area of ADEC = Area of ΔABC - Area of ΔBDE
Area of ΔABC =
=
= 18 units²
Area of ΔBDE =
=
= 4.5 units²
Area of ADEC = 18 - 4.5
= 13.5 units²
Answer:
Step-by-step explanation:
Given question is incomplete; here is the complete question.
Working together, Sam and Charlie can change all light bulbs in the office building in 3 hours. It would have taken Charlie 8 hours to do the job alone. Which equation can be be used to solve for the rate 'r', for Sam to change all the light bulbs in the office building by himself.
Let Sam can change the bulbs in the office alone in 'r' hours
Per hour work done by Sam alone =
Let Sam takes he time to change the same bulbs in the office alone = 8 hours
Per hour work done by Sam =
Since, Sam and Charlie complete the work together in time = 3 hours
Therefore, per hour work done by both =
Equation for per work done by both will be,
Per hour work done by both = Per hour work done by Sam alone + Per hour work done by Charlie
Therefore, equation for the rate 'r' will be,