Problem Solving

Adam and Brianna plan to install a new tile floor in a classroom. Adam works at a constant rate of 50 tiles per hour, and Brianna works at a constant rate of 55 tiles per hour. If the new floor consists of exactly 1400 tiles, how long will it take Adam and Brianna working together to complete the tile floor?

A)26hrs 44mins
B)13hrs 18mins
C)26hrs 40mins
D)12hrs 45mins
E)13hrs 20mins

1400 = 50(T) + 55(T)

1400 = 105(T)

T = 1400/105 = 13.33 => 13 hrs 20 min

Answer [spoiler]{E}[/spoiler]

What it the OA?

A --> 50 Tiles in 60 Mins
B --> 55 Tiles in 60 Mins

Together both A & B in 60 mins --> 105 Tiles

60 --> 105
x --> 1400

Cross Multiply
x = (60 * 1400) / 105 = 800 Mins = 13(1/3) Hrs = 13 (1/3 * 60)

[spoiler]Answer E: 13 Hrs 20 Mins[/spoiler]

Regards,
Vivek

Yup its E

SaraLotfy wrote:Adam and Brianna plan to install a new tile floor in a classroom. Adam works at a constant rate of 50 tiles per hour, and Brianna works at a constant rate of 55 tiles per hour. If the new floor consists of exactly 1400 tiles, how long will it take Adam and Brianna working together to complete the tile floor?

A)26hrs 44mins
B)13hrs 18mins
C)26hrs 40mins
D)12hrs 45mins
E)13hrs 20mins

Working together, they can lay 105 tiles an hour.
Number of hours required to lay 1400 tiles = 1400/105
= 280/21
= 40/3
= 13 1/3
= 13 hours 20 minutes

Choose E

Cheers