Say I have a table for phone commission

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Handset - TariffA - TariffB
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Nokia1 - £50 - £100
Nokia2 - £60 - £200
Sony1 - £60 - £300
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and on another sheet I have

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Handset - Expected - Actual
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Sony1 - £300 - x
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I know I have a Sony1, and that I have £300 - how do I return
"TariffB" as the cell value, X?

Any ideas on how to do this?