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Let x be the number of months in Spain;
then the number of months in Columbia is (10-x).
From the condition, you have this equation for the total of the learned words
200*x + 150*(10-x) = 1700 new words.
From the equation
200x + 1500 - 150x = 1700
50x = 1700 - 1500 = 200
x = 200/50 = 4.
ANSWER. 4 months in Spain and (10-x) = 6 months in Columbia.
Solved and explained.
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