15x + 17y = 22, 17x + 15y = 42, तर (x + y) = ?

Choose the correct question tag to fill in the blank.
I am the happiest man in my town, ________?

A hardware or software device that is able to modify data according to instructions is called a ________.
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After the word, four meanings are given. Choose the correct alternative from the following:
Directory

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'to dictate letters' mean

The underlined idiom in the following sentence means
People these days want to be rich overnight; naturally they try to earn money by hook or crook.