NOW LETS CALCULATE THE EXPENSES OF THE PRESIDENT TO CHINA.

..
the travel expenses for accompanying presidency officials is $130K, transportation $55K, accommodation $277K, honorarium $10K, contingency $20K and media coverage $10K.
 TOTAL =$502,000

NOW, converting the dollar to naira.
$502,000 * #324
=#162,648,000per tripe.

converting $2billion to NAIRA .
=$2billion * #324
=#648,000,000,000

now!
subtracting the borrowed money from the travelling expenses.
#648,000,000,000 - #162,648,000

answer:
=#647,837,352,000
instead of the #648,000,000,000. original figure ment to be borrowed he will end up bring back #647,837,352,000 after removing his expenses.