(1) A small cup of coffee contains 3.14 mole of water molecules how many H2O molecules are present.

Experts please solve this one

Chapter name -- Mole concept, Stoichiometry and behavior of Gases

Thank you

Solution :
Given, moles of water = 3.14
we know, that 1-mole water contains 6.023 $\times {10}^{23}$ molecules of water.
then, 3.14 moles of water will contain 3.14 $\times 6.023\times {10}^{23}$ =18.91$\times {10}^{23}$ molecules of water.
the answer is 18.91$\times {10}^{23}$ molecules of water.