Acircuit contains three sisters connected in a series of value of our is 200 value of our two is 640 the value of our three is 500 this sir can you supplied with six vdc what is the total voltage dropped across the three resistors

Since the sisters are all in series, they behave exactly like a single unit with resistance of (200 + 640 + 500) = 1,340 ohms.

If those three sisters are the ONLY components in the circuit, then the total voltage dropped across them is the supp[lied voltage of 6 volts.

The current through the series circuit is (6V) / (1,340 ohms) = 0.0045 Ampere.

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Note:

Next time you dictate anything, you really need to look it over before you post it, and see what your phone THINKS you said.  Then correct it where it needs correcting.