If 215.0 mL of water are added to a 237 mL sample of a 1.702 M dextrose solution, what is the new molarity of dextrose in the resulting solution?

1.702M means 1.702 moles/liter of solution

so, since we have only .237 liters, we have
1.702*.237 = 0.4033 moles of dextrose

adding 215 ml of water increases the volume to .452 liters

so, the new molarity is .4033/.452 = 0.892M