Easy chemistry question! PLEASE HELP! TEN POINTS IF YOU ANSWER!

A.)How many milliliters of a stock solution of 10.8 M HNO3 would you have to use to prepare 0.500 L of 0.530 M HNO3 ?
B.)If you dilute 30.0 mL of the stock solution to a final volume of 0.420 L , what will be the concentration of the diluted solution?

Use the formula M1V1=M2V2 where M1=initial solution's Molarity in mol/L, V1=initial volume, M2=final solution's molarity, V2=final solution's volume

A.) M1V1=M2V2
10.8M*V1=.530M*0.5L
V1=0.0245L=24.5mL stock solution
B.)M1V1=M2V2
10.8M*.030L=M2*.420L
M2=0.77M

Apply dilution law for both questions.V1M1=V2M2
A) V1=? ; M1=10.8M;V2=0.5L=500ml;M2=0.53
V1 = V2M2/M1 =500x0.53/10.8=24.54ml
B) V1=30ml;M1=10.8M ;V2=0.42L=420ml;M2=?
M2 = V1M1/V2
=30x10.8/420 =0.771M

A.)0.500 L x 0.530 = 0.265 mol. (0.265 / 10.8 ) x 1000
= 24.5 milliliters stock.

B.)0.030 L x 10.8 M = 0.324 mol. 0.324 mol / 0.420 L = 0.77 M.