In which year does the tractor maker's trend…

In which year does the tractor maker's trend reach sales of 180 thousand?

Question 62

MediumOriginal question

A tractor maker fits the trend $y = 120 + 6x$ to its yearly sales, where $y$ is sales in thousands and $x$ is years counted from 2020 ( $x = 0$ in 2020).

In which year does the tractor maker's trend reach sales of 180 thousand?

2029Correct answerYour answer2030Correct answerYour answer2040Correct answerYour answer2050Correct answerYour answer

Show the answer and explanation

CorrectNot quiteAnswer B

Correct answer: B

$120 + 6x = 180 \Rightarrow x = 10$ .
$x = 10$ is 2030.

Worth noting

2050 adds the 30 of $\frac{180}{6}$ to 2020, forgetting the 120 already there.

Concept: Solving a trend equation for the year
Typical timeTypical: 120 s
Your timeYours: —

The rule this testsA straight-line trend by least squares

Practise this chapter →

Ten questions from Time Series & Trend, at your own pace.

Practise this chapter →

Ten questions from Time Series & Trend, at your own pace.

In which year does the tractor maker's trend reach sales of 180 thousand?

Question 62

Explanation