diff --git a/src/propeller/problems/boolean/mul3.cljc b/src/propeller/problems/boolean/mul3.cljc
index 5ac2216..cea9110 100644
--- a/src/propeller/problems/boolean/mul3.cljc
+++ b/src/propeller/problems/boolean/mul3.cljc
@@ -311,6 +311,6 @@
                                 :bmx 0
                                 :bmx-umad 1}
      :single-thread-mode       false
-     :bmx-rate                 0.1
+     :bmx-exchange-rate        0.1
      :bmx-enrichment           10}
     (apply hash-map (map #(if (string? %) (read-string %) %) args)))))
diff --git a/src/propeller/variation.cljc b/src/propeller/variation.cljc
index bee5976..fb37249 100644
--- a/src/propeller/variation.cljc
+++ b/src/propeller/variation.cljc
@@ -183,7 +183,7 @@ The function `new-individual` returns a new individual produced by selection and
                          (selection/select-parent pop argmap))
                plushy1 (:plushy parent1)
                plushy2 (:plushy parent2)
-               rate (utils/onenum (or (:bmx-rate argmap) 0.5))]
+               rate (utils/onenum (or (:bmx-exchange-rate argmap) 0.5))]
            (bmx plushy1 plushy2 rate))
        ;
          :umad ;; uniform mutation by addition and deletion, see uniform-deletion for the
@@ -205,8 +205,8 @@ The function `new-individual` returns a new individual produced by selection and
                                 (selection/select-parent pop argmap))
                       plushy1 (:plushy parent1)
                       plushy2 (:plushy parent2)
-                      bmx-rate (utils/onenum (or (:bmx-rate argmap) 0.5))]
-                  (bmx plushy1 plushy2 bmx-rate))
+                      bmx-exchange-rate (utils/onenum (or (:bmx-exchange-rate argmap) 0.5))]
+                  (bmx plushy1 plushy2 bmx-exchange-rate))
                 (uniform-addition (:instructions argmap) umad-rate)
                 (uniform-deletion umad-rate)))
        ;