Bracelet costs $8. simone is also buying a necklace for her mother for $18. she believes that her total will be $98. which expression could be used to estimate the reasonableness of simone’s total? 8 × $8 + $10 8 × $8 + $18 10 × $8 + $20 10 × $10 + $10

For this case what we should do is write the expression step by step.
 "She believes that her total will be $ 98"
 To get to this we have:
 10 × $ 8 + $ 20
 Rewriting:
 10 × $ 8 + $ 20
 $ 80 + $ 20
 $ 100
 Rate approximately equal to $ 98 with an extra $ 2.
 
 An expression that could be used to estimate the reasonableness of Simone's total is:
 10 × $ 8 + $ 20

If i think this is what your asking, he should look at the grams or pounds/ounces and compare the to their cost then max can identify which one is proportional and which is not ( i think xd)