Respuesta :
Answer:
85 sociology books
255 history books
Step-by-step explanation:
h = history textbooks
s = sociology textbooks
h + s = 340
h = 3s
3s + s = 340
4s = 340
s = 85
h = 3s = 3(85) = 255
Answer:
255 history textbooks
85 sociology textbooks
Step-by-step explanation:
Define the variables:
- Let x be the number of history textbooks sold.
- Let y be the number of sociology textbooks sold.
Given information:
- Total number of textbooks sold in a week was 340.
- The number of history textbooks sold was three times the number of sociology textbooks sold.
Create a system of equations with the given information and defined variables:
[tex]\begin{cases}x+y=340\\\;\;\;\:\:\:\:x=3y\end{aligned}[/tex]
Substitute the second equation into the first equation and solve for y:
[tex]\implies 3y+y=340[/tex]
[tex]\implies 4y=340[/tex]
[tex]\implies y=340 \div 4[/tex]
[tex]\implies y=85[/tex]
Substitute the found value of y into the second equation and solve x:
[tex]\implies x=3 \times 85[/tex]
[tex]\implies x=255[/tex]
Therefore, the number of each type of textbooks sold were:
- 255 history textbooks.
- 85 sociology textbooks.