Greg needs at least $1.60 in stamps to mail a package. he has 28 cents and 4 cent stamps. he can use no more than twenty 4 cent stamps as he only has one book left.

A 5 28cent stamps And 5 4cent stamps

Number of Cents greg requires to mail a Package =$ 1.60

Number of Cents Possessed by Greg =28 cents

1 Cent = 0.01 $

28 Cent =28 × 0.01 $=0.28$

Number of cent in form of Stamp that greg has =4 Cent Stamps

Number of Cent stamps that Greg can use=24 Cent Stamp→$0.24

Amount of money that greg can spend to mail the package

  = $0.28+4×$0.24

 =0.28+$0.96

 =$1.24

 So,Greg can't mail this package, if he needs $1.60 to mail the package.

the answer is 510

step-by-step explanation:

15 • 13 = 195

15 • 12 = 180

15 • 5 = 75

12 • 5 = 60

195 + 180 = 375

375 + 75 = 450

450 + 60 = 510