@ 11wks i ahd scan i had twins, the other died and now am @ 13 weeks wil the healthy twin survive as today i had ascan& the baby is growing well?

Probably: Early loss in multiple gestations is a fairly common occurrence. If the surviving fetus is showing appropriate interval growth then chances are good that the surviving fetus will go to term. When twins share a single placenta the death of one often has a very negative effect on the survival of the second. Barring that situation or another underlying problem i think you can be hopeful.