postgresql - sql update column value using result in another table -

i have table t1

fruit | quantity ---------------- apple | 2 grape | 3 

i have table t2

factor ------   2 

i want final result

fruit | quantity ---------------- apple | 4 grape | 6 

a little confused how update since second table doesn't have id's can join on. using redshift.

select t1.fruit, t1.quantity * t2.factor t1 cross join t2