Atextbook store sold a combined total of 231 psychology and biology in a week. the number of psychology textbook sold was two times the number of biology textbook sold. how many textbook of each type were sold.

the number of psychology textbook sold that week is 154.

the number of biology textbook sold that week is 77

Step-by-step explanation:

Let x represent the number of psychology textbook sold in a week.

Let y represent the number of biology textbook sold in a week.

A textbook store sold a combined total of 231 psychology and biology in a week. This means that

x + y = 231 - - - - - - - - - - - - 1

The number of psychology textbook sold was two times the number of biology textbook sold. This means that

x = 2y

Substituting x = 2y into equation 1, it becomes

2y + y = 231

3y = 231

y = 231/3 = 77

Substituting y = 77 into x = 2y, it becomes

x = 2 × 77 = 154

x/3-10=8

x/3=18

x=48

so a parallelogram is just like a square base times height. multiply 40 and 39 to get 1560 inches.

a triangle is base times height divided by two. so multiply 7.9 and 5 and then divide it by 2 to get 19.75inches.

the kite can be split into two separate triangles and added together to get the total area. 30 x 4 /2 which equals 60. make sure to double it for the two triangles making 120.