Question 174550
The 2 trends, South American-Caribbean tourists and middle East tourists 
should be plotted as straight lines with number of tourists on the
y-axis and years on the x-axis.
The key to the problem is you have the slope (rate of change) 
and a point given for each type of tourist. The slope
and a point actually define a line, so you can plot both lines
and see where they meet.
Data for the year 2000 is given, so I'll call {{{x=0}}} the year
2000.
In millions of tourists, {{{y=40.3}}} and {{{x=0}}} for S.American
tourists. The slope in millions is {{{.8}}} per year
The point-slope formula is:
{{{(y - y[1])/(x - x[1]) = m}}} where {{{m}}} is slope
{{{(y - 40.3)/(x - 0) = .8}}}
{{{y - 40.3 = .8x}}}
(1) {{{y = .8x + 40.3}}}
---------------------------
And for the Middle East tourists
{{{y - 17)/(x - 0) = 1.8}}}
{{{y - 17 = 1.8x}}}
(2) {{{y = 1.8x + 17}}}
Solve for {{{x}}} and {{{y}}} to find where the lines meet
Subtract (1) from (2)
{{{0 = x - 23.3}}}
{{{x = 23.3}}}
Now find {{{y}}}
(1) {{{y = .8x + 40.3}}}
{{{y = .8*23.3 + 40.3}}}
{{{y = 18.64 + 40.3}}}
{{{y = 58.94}}}
This says that if the trends continue, the tourists to
both places will be equal in 2023, and there would be
almost 59 million going to each place