meaning of 'put two and two together'

[Kiriyll]

English Language Tests, Intermediate level

ESL/EFL Test #217 "American English Idioms", question 9

Ronsoon realized by putting two and two together that the salesman was trying totrick him into buying the used car. What is the meaning of 'put two and two together?' .........

(a) to renounce an idea
(b) to figure out what is going on
(c) to detain two people
(d) to do some arithmetic

English Language Tests, Intermediate level

ESL/EFL Test #217 "American English Idioms", answer 9

Ronsoon realized by putting two and two together that the salesman was trying totrick him into buying the used car. What is the meaning of 'put two and two together?' to figure out what is going on

Correct answer: (b) to figure out what is going on
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I want to know my test result. Hoping your response, and I want to see the explanation of ''
put two and two together.

Thank you
Kiriyll

[Mister Micawber]

.
'put two and two together' = to figure out what is going on.
.
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Native English teacher at Mister Micawber's