Question

Difficulty: MediumIntegers, Absolute Value, and Number Lines

On a standard number line, point RR has coordinate 18-18 and point TT has coordinate 2222. Point SS lies on the line segment RTRT such that the distance from RR to SS is 35\frac{3}{5} of the distance from RR to TT. What is the coordinate of point SS?

Answer: 6

Answer

6
The distance between R(18)R(-18) and T(22)T(22) is calculated using absolute value: 22(18)=40|22 - (-18)| = 40. Taking 35\frac{3}{5} of 40 yields 24 units. Adding 24 to the starting coordinate 18-18 gives the coordinate of point SS as 6.

Step-by-Step Solution

1
Calculate the total distance between points RR and TT
Distance =22(18)=40=40= |22 - (-18)| = |40| = 40 units
The distance between two points on a number line is given by the absolute difference of their coordinates.
2
Determine the distance from RR to SS
Distance =35×40=24= \frac{3}{5} \times 40 = 24 units
Point SS is located at a distance equal to 35\frac{3}{5} of the total segment length starting from RR.
3
Calculate the coordinate of point SS
Coordinate of S=18+24=6S = -18 + 24 = 6
Since SS lies between R(18)R(-18) and T(22)T(22), moving from RR toward TT corresponds to increasing the coordinate value by 24.

Key Concept

Calculating distance between signed integers using absolute value and finding a point dividing a number line segment in a given ratio
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