In trapezoid ABCD with AB parallel to CD, the diagonals AC and BD
intersect at E. If the area of triangle ABE is 50 square units, and the
area of triangle ADE is 20 square units, what is the area of trapezoid ABCD?
Phan Thanh Tinh Coodinator 10/10/2017 at 11:08
Draw \(AH,CK\perp BD;AM,BN\perp CD\)
So, the answer is : \(20+50+20+8=98\left(units^2\right)\)Selected by MathYouLike
Of 600 students at Goodnight Middle School in Texas, 85% are not native Texans. Of those non-native students, 60% have lived in Texas more than 10 years, and 30 students have lived in Texas less than a year. How many non-native students have lived in Texas for at least 1 year but not more than 10 years?
Nguyễn Mạnh Hùng 02/07/2018 at 08:32
We have: 30 students have lived in Texas less than a year
=> There are 5% students of 600 students at Goodnight Middle School in Texas have lived here less than 1 year.
So there 65% students are not native Texas lived here less than a year and more than 10 years.
But there are 85% are not native Texas
=> The non-native students have lived more than 1 year but less than 10 year is 20% = 120(students)Selected by MathYouLike
Currently, the sum of the ages of Yumi, Rana and Victoria is 42 years. Four years ago, the sum of the ages of Rana and Victoria was equal to the current age of Yumi. What is Yumi’s current age?
Nguyễn Mạnh Hùng 02/07/2018 at 08:39
Call Yumi's age is a
Rana's age is b
Victoria's age is c.
We have: a + b + c = 42
=> ( a - 4 ) + ( b - 4 ) + c = 36
But a - 4 + b - 4 = c
=> a + b = c + 8 (1)
We also have: a + b + c = 42
=> a + b = 42 - c (2)
From (1) and (2) we have:
42 - c = c + 8
=> 42 - 8 = 2c
=> 36 = 2c
=> c = 18
So current Yumi's age is 18.Selected by MathYouLike